Besides the optimisation of process parameters such as laser power or scan speed, the choice of the scan path represents a possibility to optimise the laser powder bed fusion process even further. The usual hatching strategy creates a homogeneous microstructure but makes it necessary to switch the laser off and on after each scan vector, which can slow down the fabrication. Moreover, the end of each scan vector is a location susceptible to the creation of keyhole pores. In this work, these disadvantages were meant to be avoided by using scan strategies that consist of longer paths and thus less end of track points. To this end, an open-source tool to tailor the LPBF G-code to geometric part features and advanced path configurations was developed and embedded into a co-visualization platform. With this tool, specimens built with four different types of paths were fabricated and the effect of these alternative scan strategies on pore distributions and path neighbourhood was investigated using micro-computed tomography. In the examined example geometry, a spiral scan pattern reduced the distance the laser had to jump between scanning by 78%. However, with the alternative path patterns, the defect architecture was strongly dependant on the part geometry and increased the overall porosity to 0.42%. Respective alleviation approaches are therefore necessary and are discussed in the remainder of this work. Laser powder bed fusion (LPBF) enables the production of highly complicated parts, based on a layer by layer consolidation of metal powder following distinct exposure strategies of a computer controlled laser beam. The laser movements are planned with a special software called the slicer, which is responsible for placing the scan vectors and setting the machine and laser parameters. The slicer is supplied with the geometry of the part—for example, in .stl format, the position and orientation of the part on the build platform and the machine parameters to be used. The slicer then calculates the trajectories for each layer and outputs the numerical control code containing commands to set machine parameters as a file that can be read by the machine. In LPBF these commands include the setting of the laser power and the scan speed. The coordinates of the toolpath are transformed to orientations of the scanner optics to position the laser spot, while laser on and off commands control which part of the trajectory belongs to the part that is to be melted and which parts are used to reposition the laser spot between laser on commands.The slicer software in LPBF is usually proprietary software supplied by the machine manufacturer and can only be used with certain machines of that manufacturer. Since the slicer controls the process of fabricating a part, it also affects the quality of the part, for example, porosity and residual stresses. For example, Parry et al. found that the placement and length of scan vectors influenced build up of residual stress through changes in thermal history of the parts . AccordiXiong et al. investigated the influence of a time optimal hatching direction to minimise the count of laser on/off switches which increase scanning time due to the need for delays by the scanner system . DependeSince the slicer supplied by the machine manufacturer often offers no possibilities to manipulate the path generation, researchers have taken different approaches to overcome this limitation. Parry et al. circumvented the machine’s slicer by developing his own tool for planning the laser trajectory . For thiIn the following, another methodology for creating LPBF build jobs is presented, which works by modifying build jobs from an open-source slicer for fused filament fabrication (FFF). The novel method is used to create three novel scan patterns. These scan patterns are evaluated with descriptive statistics for their influence on the laser on/off count and the build time. To keep the analysis machine independent, the impact of the scanning strategy on build time is evaluated through the analysis of descriptive statistics of the path. This makes the results independent of the delay times and acceleration characteristics of the scanner optic used. Specimens fabricated with the scan patterns are subsequently analysed with µCT for porosity distribution.−1, a layer height of 30 μm and a scan line spacing of 150 μm. The parameters used were selected based on previous research  the commands M45 and M46 are used to turn the laser on and off. Although the commands are machine specific, the general approach should be possible on most LPBF machines. Since all operations and conversions are conducted on an intermediate representation of the build job, only the parsing and output modules have to be adapted for other machines.To do the changes on the G-code, a C++ program was developed. The program parses the FFF G-code and stores it in an intermediate representation containing the coordinates of the trajectory and metadata for each path point. The metadata consist of the feed rate, nozzle temperature and extrusion quantity. To use the G-code in an LPBF machine, the parameters have to be reinterpreted. Therefore, the nozzle temperature is interpreted as the numeric value for laser power. The extrusion amount is not needed for the LPBF process but could be used as additional parameter for path width control in future work. In this work, the extrusion amount is only needed to distinguish between movements for which the laser should be switched on and movements for which the laser should be switched off.https://sourceforge.net/projects/ctfam/ (accessed on 22 December 2021). The trajectories used for the fabrication of the four specimens and the resulting pore distribution will be analysed in detail in the following.Through this procedure, a build job was prepared to build four specimens with different scanning strategies. Another tool was used to convert the G-code to a .vtk file containing the trajectory and metadata for visualisation in Paraview . This prFour different strategies were evaluated. As a baseline, the hatching strategy was examined. The hatching strategy consists of two paths following the contour (perimeter) and a hatching for the inner part that is rotated about 67° each layer. The spiral strategy fills every contiguous area with only one continuous spiral path. Therefore it offers the highest potential for a reduction of laser off moves. The perimeter strategy fills areas with paths following the contour concentrically. Since this type of fill strategy can create areas where the line spacing between two lines is greater than the specified spacing, but too small to place another line between these lines, a variation of this strategy was investigated. In this perimeter fill strategy, a scan line, which is allowed to fall below the line spacing, was placed in those areas.strategy d places In the following, the strategies are characterised by features such as the number and length of the paths required. The perimeter strategies have thus reduced the count of paths with the laser switched off, but the total length of paths with the laser switched off is even higher (about 20% respectively 29%). The spiral strategy on the other hand led to greatly reduced off/on switch count as well as path length with the laser switched off.The specimens were analysed in µCT to gain insight into differences in porosity characteristics. To this end, the layer visualised in The projection images in In order to assess the pores constituting the porosity values, all pores of the four samples were sorted in descending order according to their volume and then plotted in the double logarithmic diagram in The number of defects between weld tracks increased for every strategy compared to the hatching strategy. The shown examples demonstrated how the visualisation of the generated scan path, together with the resulting defect microstructure, facilitates the understanding of defect formation. It is assumed that the rotation of the hatching allows the defects to “heal” because the weld depth exceeds the layer height, thus closing the pores between tracks in subjacent layers. When developing new scan strategies, these peculiarities should be taken into account by placing paths so that defect-prone locations such as acute angles and areas between tracks are not located at the same spot over multiple layers. With the perimeter strategy, this could be achieved, for example, by changing the line spacing of the outer perimeter line to half of the specified line spacing in every second layer. This modification would place the scan lines exactly in the area between the scan lines of the last layer, allowing for the “healing” of previous layers. This would also reduce the size of spots exceeding the desired line spacing. An example is provided in the supplementary material in The development of new scan strategies could be further aided through the free modifiability of the G-code in the intermediate representation, similar to the strategies developed by Yeung et al. . As showAdditively manufactured specimens fabricated using novel scanning patterns were analysed in terms of pore distribution. The trajectory used for fabrication of the specimens was evaluated with regard to the required path length and locations that were particularly critical for the formation of defects.The perimeter strategy offered no advantage in terms of required path length but reduced the number of laser on/off cycles;The spiral strategy, on the other hand, drastically reduced the number of laser on/off cycles and also reduced the distance the laser had to travel when switched off;All concentric strategies resulted in spots that exceeded the desired path spacing. In addition, there were inadequately covered spots at acute-angled kinks in the path;Keyhole pores at the start and end of tracks were reduced by using the concentric strategies. Nonetheless the concentric strategies resulted in higher porosity due to a change in the dominant pore formation mechanism;These spots ultimately also led to large lack of fusion pores visible in the µCT images. Filling of the spots exceeding the desired path spacing with lines with a line spacing falling below the prescribed spacing prevented the formation of the lack of fusion pores. In contrast, this approach was not possible at the defect prone locations linked to acute path kinks;Porosity in the concentric scanning strategies was concentrated between scan lines. This was attributed to the missing change in scan vector placement in subsequent layers. In the hatching strategy, this variation in path placement allows to remove defects of subjacent layers;The concentric scanning strategies resulted in a higher porosity and at the same time increased pore size compared to the hatching strategy. Although the end-of-track pores could be reduced, the described formation of the lack of fusion pores increased the porosity.As an outlook, the free modifiability of the G-code in the intermediate representation allows the creation of further optimised scanning strategies. Moreover, the understanding of pore formation due to acute path kinks or exceeded path spacing can be used to introduce intentional pores to locally improve the specific material properties. The generation of pores via the path enables precise process control without having to sacrifice accuracy via CAD. Similarly, graded lattice structures could be fabricated, analogous to the approach in the FullControl GCode Designer by Gleadall, which uses the extrusion amount to grade lattice properties of FFF fabricated lattices . Althoug


The nature of the trajectory and the mean displacement velocity of the part mainly depend on the width of the rectangular function for dynamic dry friction control. To verify the theoretical findings, an experimental setup was developed, and experiments of manipulation were carried out. The experimental results qualitatively confirmed the theoretical findings. The presented analysis enriches the classical theories of nonprehensile manipulation on oscillating platforms, and the presented findings are relevant for mechatronics, robotics, mechanics, electronics, medical, and other industries.This paper presents a novel method for nonprehensile manipulation of parts on a circularly oscillating platform when the effective coefficient of dry friction between the part and the platform is being dynamically controlled. Theoretical and experimental analyses have been performed to validate the proposed method and to determine the control parameters that define the characteristics of the part’s motion. A mathematical model of the manipulation process with dynamic dry friction control was developed and solved. The modeling showed that by changing the phase shift between the function for dynamic dry friction control and the function defining the circular motion of the platform, the part can be moved in any direction as the angle of displacement can be controlled in a full range from 0 to 2 Two-dimensional manipulation and transportation of various objects are commonly used in many fields such as research, various industries, and medicine. There are many processes in manufacturing where objects/parts require sorting, positioning, transportation, orientation, classification, and/or assembly. These tasks can be carried out using either prehensile or nonprehensile methods. Prehensile methods usually involve grasping by some sort of grippers. In the case of nonprehensile manipulation, the parts to be manipulated are subjected only to unilateral constraints, e.g., placing an object on a platform. Nonprehensile manipulation methods have a lot of advantages, such as when there is no involvement of gripping, picking up, or other type of force or form closure, the stress on the part is minimum, workspace can be large, and lower operational times are required. A major advantage of nonprehensile manipulation is that it can be achieved with relatively simpler technological equipment.Parts on a horizontal platform can be moved by various means. For example, this can be performed by using parallel manipulators ,2,3,4 byMethods utilizing vibrations are very versatile as they can be applied to manipulate objects of various sizes . Additionally, these methods can be applied to manipulate high temperature parts at contaminated environments, and they are suitable for individual parts and bulk materials. Moreover, they do not require expensive and complex equipment. Therefore, these methods are being extensively studied in scientific literature and applied in industrial practice .There were many attempts to employ flexural vibrations induced in vibrating plates for nonprehensile manipulation task as the position and orientation of the particle can be controlled depending on the node shapes of the plate induced by particular frequencies ,23,24,25Frictional forces play a major role in nonprehensile manipulation methods that employ vibrating platforms. To make a part move on an oscillating platform, an asymmetry must exist to ensure that net friction forces over one oscillation cycle do not cancel out. Frei et al.  demonstrMayyas  analyzedReznik et al.  studied Fedaravičius et al.  proposedThe literature review showed that an asymmetry is a necessary condition to achieve the part’s motion on a periodically oscillating platform. Temporal, spatial, or force asymmetries are commonly used in nonprehensile manipulation systems that utilize vibrations. The novelty of this work is that a horizontal platform subjected to circular oscillating motion is employed for omnidirectional nonprehensile manipulation while other systems employ other types of oscillating motion, and a frictional asymmetry is created by dynamically controlling the effective dry friction between the part and the platform instead of temporal, spatial, or force asymmetries that are commonly used in other nonprehensile manipulation methods that utilize vibrations. The effective friction force can be reduced by exciting high frequency vibrations ,38,39,40The dynamic model of manipulation of a part on a circularly oscillating platform using dry friction is shown in t is time, eA is the excitation amplitude (the radius of the circular motion), ω is the angular frequency of the circular excitation, and ε is the phase shift between the harmonic waves along the ξ and η axes .The manipulation system consists of a horizontal platform excited in two perpendicular directions by harmonic excitation with a phase shift:It is assumed that the part is flat, and the mass of the part is concentrated in the mass center. When the part is sliding in respect to the platform, the projections the acceleration of the mass center are written as follows:frF that acts opposite to the relative velocity expressed as The part’s motion on the platform is influenced by the dry friction force Then, the following equilibrium can be written:μ(ωt) is the rectangular function for dynamic dry friction control. Inserting Equations (2) and (3) into Equation (4), the equations of motion of the part on the platform are written as follows:n = , µ1 is the nominal dry friction coefficient between the platform surface and the part, µ2 is the dynamically reduced effective dry friction coefficient, ϕ is the phase shift between the function for dynamic dry friction control and the function defining the circular motion of the platform, Δτ is the width of the rectangular function for dynamic dry friction control . The principle of dynamic dry friction control is presented in The parameter Δ−4 s was defined to ensure numerical stability of solution at every time step. The absolute and relative tolerance of the solver was set to 10−6. These parameters yielded stable and reliable results of the analyzed problem at a reasonable simulation time.A numerical modeling of part manipulation was carried out. The modeling software was developed in the MATLAB  programing language and the motion equations were solved numerical by using the Runge-Kutta ordinary differential equation solver ode45s with an adaptive time-stepping scheme. A maximum integration step time of 10µ = const) [µ ≠ const). This sort of dynamic dry friction control allows one to control the motion of the part as well. The nature of the part’s motion depends on the dry friction control parameters  . To makerameters . TherefoP1 and the ending point P2 of the trajectory .The modeling of the manipulation process with dry friction control showed that both the direction and the velocity of the motion of the part can be controlled over a wide range by changing ds on Δτ a,b. Whenϕ , the displacements are significantly lower, and the trajectories are more circular (τ (Δτ = π) presented in τ is associated with the level of the asymmetry of the analyzed system, the trajectories at the higher value of Δτ are less stretched and the displacements are significantly higher in The angle of displacement  shift ϕ . Figure circular a comparev of the part was determined. The mean displacement velocity v was calculated by dividing the covered distance after 20 circular oscillation cycles by the traveling time. As Δτ increases up to 3π/2, the mean displacement velocity v also increases , a negligible influence of eA on the displacement angle α was observed  to be manipulated which is placed on a platform (2) mounted on four elastic rods (3) a. The upτ in each period of the circular excitation of the platform with a phase shift of ϕ. The frequency of the high-frequency excitation for the piezoelectric actuator was 5890 Hz. The piezoelectric actuator was periodically exciting vertical vibrations of the platform’s upper surface with an amplitude of 0.5 µm. When the piezoelectric actuator is activated, the effective friction force is reduced as a result of the dynamic processes, which occur in the contact between the part and the platform. Employing this technique, the effective dry friction force between the part and the platform can be dynamically controlled in a predefined manner. The output from the optical reference sensor as well as the signal for the piezoelectric actuator generator are monitored by a digital oscilloscope (12) .The phase of the circular excitation is monitored by an optical reference sensor (8) . The signal of the optical reference sensor is processed by a vibration analyzer (9) . The signal of high-frequency excitation for the piezoelectric actuator is generated by an arbitrary waveform generator (11)  and amplified by a piezo linear amplifier (11) . The signal for the piezoelectric actuator is composed of high frequency pulse sequences, which are synchronized in respect to the phase of the circular excitation. Similarly, like it is shown in A high-speed camera (13)  was used to record the displacement of the part. The camera was equipped with a Canon MP-E 65 mm f/2.8 1-5x Macro Lens. The camera was controlled by a computer (14). To digitize the displacement of the part, a video processing program was developed, employing the normalized cross-correlation approach.ϕ6 × 0.8 mm, 0.201 g).Using the mechatronic system shown in α can be controlled by changing the phase shift ϕ . Also, the mean displacement velocity v increases as Δτ increases. This is attributed to a higher asymmetry of the system. However, when a critical value of Δτ is exceeded, v starts to decrease since the system asymmetry becomes lower again.A mathematical model of the proposed manipulation method was developed and solved numerically to provide a theoretical verification of the functionality of the proposed method as well as determine the control parameters that define the motion characteristics. The modeling results showed that by changing the phase shift α on ϕ, α on Δτ, and v on Δτ obtained by the model showed a good agreement with the experimental values. The experimentally captured nature of the part’s motion was close to the one observed in the modeling results.To verify the theoretical findings, an experimental setup for manipulation of parts on a horizontal circularly oscillating platform with dynamic dry friction control was developed and manufactured. The experimental results qualitatively confirmed the theoretical findings as the dependencies of The research results demonstrate that the proposed method of creating a frictional system asymmetry by employing dynamic dry friction control can be applied for conveying and omnidirectional nonprehensile manipulation tasks. As the technical equipment for the implementation of this method is relatively simple and compact, from the practical point of view, this method is very versatile and can be used in various environments with objects/parts of various sizes.The presented analysis enriches the classical theories of nonprehensile manipulation on oscillating platforms, and the presented findings are relevant for mechatronics, robotics, mechanics, electronics, medical, and other industries.


This study seeks to explore how social workers have perceived and experienced a medical home model for children and adolescents in out-of-home care in Uppsala County, Sweden.A qualitative explorative study was conducted, which involved ten semi-structured individual telephone interviews with social workers. The study sample included employees within the social service, working in a specialised case unit who had experience of referring children and/or adolescents to the medical home model called Hälsofam. Data were analysed inductively using thematic analysis.all children and adolescents have the same possibility to receive care from Hälsofam.The findings of the current study indicated that working with Hälsofam has offered social workers a way into the health care sector and an active collaborative working situation, with focus on organised work across the ‘silos’ of care services. However, the findings raised the question of whether or not The findings indicated that the Hälsofam model had a positive impact on the interrelations between the social service and the health care sector. Yet, findings showed that personal views of the social worker and the societal situation in which they operate create limitations for providing care for every child and adolescent. This study adds to the extant literature for it addresses the limitations within the work of children and adolescents in out-of-home care.The online version contains supplementary material available at 10.1186/s12913-021-06737-1. In Sweden, outcomes for children in out-of-home care (OHC) have been disappointing . They arIn 2018, Swedish statistics showed that 38,800 children and adolescents were placed in care by The National Board of Health and Welfare . ‘PlacedIn accordance with The Swedish Local Government Act SFS; 2017:725 , local acompulsory care received health assessments to a higher extent than children and adolescents placed in voluntary care.To date, research on health assessments of children and adolescents in OHC shows a low percentage of referrals . In natiMedical home models are widely supported . In 2007In an evaluation of the societal costs of organisational models for health care of children and young people in OHC , the iniThis qualitative research study seeks to address the need for further studies on the topic.Hälsofam is a medical home model for children, 0–17 years old, investigated by the Child Protection Services (CPS) and provides multi-professional coordinated consultation and care . The focThe Hälsofam user group is children, 0–17 years, living in or near Uppsala region. In 2019, the population of children in the age between 0 and 19 were 522,33 out of the total population of 230,767 . In the In a case review from 2020, thirty randomly selected Hälsofam Electronic Medical Records (EMR) of children aged 0–17 years from April 2016 to April 2019, were studied . The aimThe Hälsofam process commences with a multidisciplinary assessment taking place when a child enters the service. This includes a physical exam, a developmental assessment by a paediatrician, a psychological assessment by a child psychologist and, if required, referrals to associated health services. The assessment concludes in a health report delivered to CPS. The model includes, on average, two follow up visits in the first year. The child is followed up even if the current OHC placement is in another region. Follow up with the birth family is offered if the child exits care or the court does not approve CPS placement. The follow up is tailored to the child’s individual needs. A handover takes place when the form of care changes. Hälsofam personnel coordinate with CPS regarding the child’s health plan and match with placement and (proposed) multi agency quality assurance at the child level.Although there is an acknowledged lack of empirical research on organisational models within the field of health and dental care for children and adolescents in OHC, a body of literature exists on multidisciplinary team responses to child abuse. A recent scoping review  of crossAs key stakeholders in the model, there is a need for clarification around how social workers perceive Hälsofam. Previous research indicates that social work activity is influenced by role expectation . The Hälsystem of the person, as the immediate setting for an individual. The microsystem is described as a set of activities, functions and interpersonal relations perceived by the individual in a setting. In the current research it was used to study the setting for social workers and the interactions, activities and roles that they experience at their workplace, working with Hälsofam. The mesosystem refers to the interrelation between two or several settings in which the individuals have active roles. For this study, it was used to consider the interrelation between the Hälsofam personnel and the staff at the social service. The exosystem refers to one or several settings that affects or are affected by a setting that do not involve the individual as an active actor. It was used to study how the social workers were affected by the setting of the Uppsala County and Hälsofam including, but not exclusive to, policies adopted by the organisations.The ecological theory , emphasiHälsofam is currently delivered by the Child Protection Team at Uppsala University Hospital. Uppsala University Hospital is one of the seven University hospital in Sweden. The service gives priority to the eight municipalities within the region but are available for nearby municipalities. In Uppsala County, the eight municipalities are themselves responsible for the social service within their area.The Hälsofam user group is children, 0–17 years, living in or near Uppsala region. In 2019, the population of children in the age between 0 and 19 years was 52,233 out of the total population of 230,767 . In the i.Employees within the social serviceii.Social workers, working in a specialised case unit with long-term careiii.Experience and knowledge about referring children and/or adolescents to HälsofamThe study population consisted of social workers. A mix of purposeful sampling and snowballing sample technique was used to collect participants. The criteria of inclusion in the study sample were:In terms of sample size, the target was to reach an initial analysis sample of 10 social workers. If no new information had emerged from the last 3 conducted interviews, then recruitment would stop. However, if new ideas were emerging then more social workers would be recruited. This would continue until no new ideas were raised. This was defined as having a stopping criterion of 3 . Within Contact was established with supervisors and social service personnel from March to May 2020. The process began, by guidance of Patton , by askiThe participants were recruited by virtue of their professional role, therefore ethical committee review was not required. When recruiting within Uppsala County, approval of responsible supervisors was collected before the social workers were contacted at the request of senior personnel within the County. To ensure that the respondents made an informed decision to participate, they received written information by email. The responsible researcher then offered the possibility to pose questions. If the social workers wished to participate in the study after receiving the information, their written informed consent was collected.i.social worker’s personal perspectiveii.the influence of the workplaceiii.the interrelation between social workers and Hälsofamiv.outside organisation influenceData were collected between March and May 2020 through individual interviews conducted by telephone. The duration of the interviews were approximately 7 to 20 min, with an average of 15 min. The research was conducted through a qualitative explorative study. Qualitative research was chosen due to its eligibility to study people’s experiences and perspectives . Semi-stDue to the situation of the Covid-19 virus, it was not preferable to perform the interviews as face-to-face meetings. The interviews were therefore conducted by telephone. All interviews were recorded with two digital voice recorders, with given consent of all the participants.A systematic qualitative content analysis with an inductive approach was used to analyse the data . The datA total of 10 social workers took part in the study, 9 within the Uppsala Region and 1 outside of the Uppsala Region. With a degree of Bachelor of Science in Social Work, there are many possible work positions . Of the A way in - captures the social workers’ experiences of finding a way into the health care service for the children and adolescents on their caseload. See Table Collaboration in action – captures the working relationship between the social service and Hälsofam, and other related services. See Table For every child and adolescents? – describes the factors that appear to affect participation in the Hälsofam model. See Table Three main categories emerged from the analysis. The main categories and sub-categories are presented in Table “The first contact” is based on how the social workers talked about the perceptions of the first contact with Hälsofam. For social workers, those outside of Uppsala County had their first contact with Hälsofam through a Google Search. They had desperately been searching for a solution to their problem gaining access to health care for their cases and expressed great gratitude for finding Hälsofam. Other social workers within Uppsala County were introduced by colleagues or received information directly from the team. Being introduced by a colleague was perceived positively. Whereas some experienced the information about Hälsofam via a standard informational routine, which aimed to remind the social workers to use the team and how to use them.In terms of parents and legal guardians’ first contact, one respondent described several scenarios when they had been searching for information on Hälsofam online and were affected by negative publicity and a perceived ‘bad reputation’. That first contact resulted in worried parents, aroused suspicion and fear of what could happen if their child came in contact with Hälsofam. The parents’ first contact had affected the respondent’s work negatively.“An end to calling around” is based on the previous experiences of the social workers, being forced to call around to doctors and health care centres, trying to book appointments for children and adolescents. Several respondents shared their previous experiences of the time-consuming process of phoning doctors and health care centres, having their calls being put on hold and not having the possibility or knowledge to get in contact with the right actor. Their perception of Hälsofam was that now they had a direct, efficient contact point. By being given access to the Hälsofam network and their connections, they experienced that they got the right support faster. In cases where the Hälsofam personnel could not help them directly, they experienced that the team could help them with referrals to other health care actors.When considering collaboration and coordination, the low staff turnover within Hälsofam is discussed by several respondents. The experience that the social workers have been able to create and maintain a personal relationship with the team is appreciated.Those who reported that they had a close contact with the team, emphasised that the work was perceived easier with a personal relationship. They described the experience of having met the same people from day one of their work and the comfort and support that brought.Some respondents also highlighted the positive effects on the children and adolescents, and other actors within the process, who witnessed this relationship. They perceived it being positive that others could experience their good relationship, creating a sense that the social service and the Hälsofam personnel worked together for the child or adolescent.All the respondents had the perception that Hälsofam worked with another point of view than the social service and other actors within the health care sector. Previous experiences have been that other actors only focus on their specialism. For example, Child Psychiatry Teams focused only on mental health, and Child Health Centres only focused on physical health. Hälsofam, on the other hand, have enabled assessments that include mental, dental and physical health as well as seeing to the context around the child or adolescent. At the question of the purpose of the Hälsofam model, the social workers witnessed an understanding of possible parental behaviour in the kinds of situations experienced by children in OHC, as well as knowledge of social inequalities and potential exposure to violence and threats. Being sensitive to other relevant perspectives, other than just “your blood tests look okay and you have a normal height”, created a more holistic point of view of a child’s or adolescent’s health status. The majority described this as something unusual, compared to other actors within the field.The social workers described their perceived limitation within the field of health care and lack of medical knowledge. Several of the respondents had the experience that Hälsofam had been of valuable help in the work of mapping the health status and medical history of children and adolescents. The specialist expertise of the Hälsofam personnel, beyond that of social workers, was clearly evident to the participants, with several speaking to the value of having a trauma psychologist connected to the team. In some cases, children and adolescents could have been experiencing several placements in different municipalities and sometimes other regions, making it difficult for the social worker to trace the medical history. Some respondents experienced that the Hälsofam personnel had then been able to assist the work in finding medical records from a young age. Yet, others wished for an even greater holistic approach within the medical field and the requisition of relevant information.All 10 of the respondents agreed on the perception that the Hälsofam personnel were a committed medical team. They argued that the team at its core were loyal, sensitive and dedicated in their work towards a better health for children and adolescents in OHC. With this focus, some experienced that “their” children and adolescents had developed a more trusting and responsive approach to the health care sector.Several of the respondents spoke about previous experiences of children and adolescents “falling through the cracks” in the work process of other institutions. Their experiences were that the Hälsofam personnel have been dedicated and eager to ensure that they fulfil their responsibility and provide the child or adolescent with necessary care. They experienced that the personnel were being committed and willing to go that extra mile for the children and adolescents. Some social workers reported a sense of the team being generous with their knowledge and time, and that the team “wants to be there, they want to help you and the child”.Several respondents discussed the rights of the child and the different responsibilities of various actors, to ensure those rights. Some respondents perceived that the Hälsofam personnel ensured that the different authorities and legal guardians met their responsibilities towards the child. They had the experience that Hälsofam framed and coordinated the different responsibilities, so that everyone worked together for the sake of the child.The respondents argued differently, where some perceived that it was a shared societal responsibility to care for the child and adolescent. Others argued that actors should work separately and meet the responsibility within their profession.One respondent had the experience that Hälsofam personnel highlighted, framed and ensured the legal security for the child and adolescent, for the legal guardian, for the residential care homes and for the social service. The respondent argued that it was essential to know the medical history of a child from the very beginning of the social care, to ensure the right actor is to hold responsible for any potential injury, sickness or ill-health. Several respondents also argued that the Hälsofam personnel more clearly stated the responsibilities according to Swedish legislation.The level of participation of the individual social worker was something that the respondents discussed in different ways. Some respondents considered it important to attend the health assessment process, and therefore prioritised it. They had the perception that they were included and welcomed into the process, with a positive feeling that the Hälsofam personnel and the social service had a shared responsibility throughout the process and that the child or adolescent were “their common child/adolescent”. By being present they experienced a deeper understanding of how the social service could provide better support for the child or adolescent, and that meetings in person enabled better dialogues between the actors.Other respondents did not, to the same extent, report the same interest of participation. They were present over the telephone and did not express a wishing of being present in person. Some respondents perceived that they got the relevant information they needed from verbal and digital communication.The respondents that expressed an interest in active participation reported a higher usage of the team. They consider it being important to refer children and adolescents in the process of OHC to Hälsofam. On the other hand, the respondents that expressed a lower level of interest in participation and attendance, reported to a higher extent that they used Hälsofam “sometimes”, “for some children” and/or “whenever they remembered to have them in mind”. This finding highlighted an inequality, that an interest in participation could have an impact on whether or not a child or adolescent received care from Hälsofam.The high workload within the field of social work affected the actor’s ability to perform equivalent work efforts for every child or adolescent. The high workload was prominent both within the social service and in Hälsofam. The social service as an authority experienced a high workload, forcing the social workers to sometimes choose the ‘easiest way’. Taking meetings and briefings over the telephone were given as an example of this. The social workers’ ability to be present throughout a process could therefore be due to the workload and/or the work routines within the profession.The process of referring to and working with Hälsofam was perceived as time consuming for some respondents. The fact that different professions within the social service had different workloads and working conditions, was raised by some respondents as a somewhat ‘unfair’ situation. Being a referral investigator or case worker could in some cases affect the prerequisites to participate and have an active attendance for every child and adolescent. Referral investigators tended to work a heavier caseload and thus have less capacity per child, whereas a caseworker had more time to dedicate to each child on their caseload. Some participants expressed that Hälsofam actually added to their workload, having the perception that they might see too much to the child’s every expressed need. They would argue that it resulted in a lot of extra work for the social worker.The workload in the health care sector was also an argument for the inability to work for every child or adolescent. Some respondents could experience difficulties in being able to book appointments at Hälsofam when they needed to, with an argument that “it is the situation of the society today”.The purpose of this research was to study how social workers perceive and experience the Hälsofam model. In the problem explanation, it was stated that a well-functioning system of health assessments and examinations is necessary to discover potential health issues concerning children and adolescents in OHC. Basic preventive needs have been unmet and there has been a need for a comprehensive and continuous system.microlevel of the ecological model can be used to understand the findings in the perceived first contact with Hälsofam [The respondents’ perceptions and experiences have, from different perspectives, described to what extent Hälsofam has worked as a well-functioning system. The first impression was prominent in participants’ responses. The Hälsofam . LookingHälsofam . PreviouHälsofam . It is tmesosystem in Bronfenbrenner’s ecological model [The Swedish health care system has been under pressure since the 1990s, following increased critical observation and demand for cost-containment . Althougal model . This ‘wal model .mesosystem [The social workers’ perception of Hälsofam was strongly connected to the collaborative nature of the work. Relationships and the sense of commitment were very important to some of the respondents, creating a deeper meaning of the collaboration than just performed tasks. Personal relationships and commitment within the medical team, are in line with the structure of the sosystem . Positivsosystem , 47, witsosystem , 48, 49.exosystem [.Some participants emphasised the relevance of high standards within the work performance, the ability to work inter-professionally, and responsibility towards the child or adolescent. This aligns with previous research findings that emphasise professional skills and knowledge as key to cross-agency working . For exaxosystem .every child or adolescent in OHC. An inequality emerged from the interviews, showing that the usage of the Hälsofam care depended on the personal interest and the experienced workload of the individual social worker. This can be understood from Bronfenbrenner’s definition of the person [exosystem [Despite the improved work experiences and the positive perceptions, there appeared to be a form of selection bias with regard to which children and adolescents were referred. This could be interpreted as the model not achieving the goal to fulfil the basic needs of e person . Beyond e person . In conne person , 54, 55.xosystem . The newxosystem , implemexosystem .The findings of this study emphasised the relevance of positive interrelations to succeed with co-ordination and collaboration. The limitations, based on the research findings, showed that potential inequalities could occur when decisions of Hälsofam usage were linked to the social workers’ personal views and decisions. Other limitations could come from the societal situation in which the social service and Hälsofam operate. Societal responsibility, and the resulting heavy workload, affects to what extent the social worker is able to work for every child or adolescent in the same way. This creates a somewhat unjust situation for the child or adolescent, being dependent on the personal views of the social worker and the situational workload at the moment.Strengths of this research was having several people involved in the data analysis and analysing the research findings according to a pre-chosen theoretical framework. By that, the reconstruction and representation of the social workers’ narratives were according to the reality of the ecological theoretical framework and not according to the personal interpretation of the responsible researcher. By using the method of verbatim interview transcripts, an interview guide and an interview protocol, the research limited irrelevant interpretation of the data. The interpretations of the findings were confirmed by using quotations from the verbatim interview transcripts. To ensure a logical, traceable and documented working process the research was made by describing the research design thoroughly, including the planning, recruitment, data collection and analysis process.Potential limitations of this paper were since the aim of the current research was to study the experiences and perceptions of social workers, specifically concerning the Hälsofam model, it was a very narrow field. Given the reliance on only the social worker perspective, the application of the ecological model was somewhat limited; however, the application of the model was intended to broaden the scope of the social workers’ responses to consider the various systems in which Hälsofam can be interpreted.Another potential limitation was the sampling method. Due to the situation of the Covid-19 virus, the studied group of professionals were difficult to establish contact with within the timeframe of the research. Therefore, a mix of purposeful sampling and snowballing sampling was conducted. As Hälsofam representatives initiated the purposeful sampling, there is a risk of biased perspectives whereby those who would give a positive interpretation of the model were selected. Snowball sampling also involves the limitation of not being able to provide a representative sample, because of the risk to only reach respondents with similar point of views. The lack of representation of the municipalities could also be considered a limitation. Within Uppsala County, there are 8 municipalities. All 8 have an established collaboration with Hälsofam. In the current research, two municipalities within Uppsala County and one within Stockholm County  were represented. A further limitation was the short length of the interviews, which could be a result of the interview guide being too narrow, or too few probes and follow-up questions . A commoThe findings of this study emphasise the importance of the organisation for health assessments of children and adolescents in OHC. The collaboration between the social service and Hälsofam has several reported strengths. A perception of a strengthened organisation and work force, and an improved working process concerning availability, competence and effectiveness are all positive improvements that were reported. The limitations of the Hälsofam model uncovered by this study point to the importance of creating routines and structures for usage of the Hälsofam model, as well as the relevance of more support and resources to this societal activity. An important direction for future research could be to examine experiences and attitudes of others connected to, and involved in, Hälsofam. Interviews children and adolescents with experiences of being referred to Hälsofam would give valuable insights on how the collaboration and work process have been perceived by those in need of care. To examine the attitudes of parents and caregivers, and other actors involved in the Hälsofam work, would be useful to support the future well-being of Hälsofam users.Additional file 1.