Instructions: Below is a detailed instructional guide to producing a functioning Brace assembly from the provided CAD files. Sizing guide Measurements for brace sizing are best taken using a flexible measuring tape. Ideal dimensions will vary between individuals, and care should be taken to ensure the accuracy of recorded measurements. The current brace revision is designed as a generic and symmetrical assembly that is capable of being worn on either leg. Advanced CAD modeling skills in conjunction with in-depth knowledge of the anatomy of the lower leg could lead to a very precise end product. As the model stands now, the sizing instructions for the critical dimensions are outlined below Model Manipulation The dimensions discussed below must be obtained prior to CAD file manipulation to ensure a proper fit to each individual. The current model was constructed using Solidworks as the CAD software. All size adjustments can be conducted within the top level assembly file. 2 1 5 3 4 Front View Side View Top View The vertical distance between the center of the upper and lower cross supports and the center of the hinges (dimension 1, seen in the front view) can be adjusted by manipulating the distance2 mate for the upper and distance5 mate for the lower in the assembly mate group. To adjust, right click on the mate, click on edit feature, and input the desired dimension in the distance box.
The horizontal spacing between the inside wall of the two hinges (dimension 2, seen in the front view) can be adjusted by manipulating the distance1 mate in a similar fashion as outlined above. The offset distance of the upper and lower cross support from the center of the hinge (dimension 3, seen in the side view) can be adjusted by manipulating the distance4 mate for the upper and distance6 mate for the lower in a similar fashion as outlined above. The Radius and wrap angles of the upper and lower cross support (dimensions 4 & 5, seen in the top view) can be manipulated by editing the individual part files of each component. To edit a part file while inside of the assembly file, double click on the component of interest to display all internal feature dimensions than can be edited. After editing, initiate a rebuild (CTRL + Q) to implement the changes into the assembly. Part files will automatically be updated but will require a save for the changes to permanently take effect. It should be noted that as currently designed, the size of the upper and lower connectors are derived based on the position of other components in the assembly. Manipulating any of the above dimensions should automatically update the size and shape of the four connectors after performing a rebuild. Also of note, the two hinge assemblies are designed to be printed as a pre-assembled component on a printer with dissolvable support material. If such resources are not available, the hinges will likely need to be redesigned as two separate components (inner component and outer component). File Creation Upon updating the CAD files to satisfactory sizes, the assembly must be saved in a format that can be interpreted by the 3D printer being used to produce the parts. Different printers require different file formats, but for this guide the.stl file type will be highlighted. STL files are widely used and are accepted on many of the printers in production today. If the printer being used requires a file type other than an STL, consult the instructional guide for that specific printer model to obtain information about the necessary file type. To save a file as an STL, select Save As from the File tab, and select STL from the drop down file type box. Click on the options button to edit specifics of the STL like resolution and unit type. Of special note, the save all components of an assembly as a single file box should be checked when saving STL s for the left and right hinge if dissolvable support material is being utilized. Otherwise, the box should be unchecked to produce STL s of the individual components. An STL file is required for each individual component of the Brace assembly. The process is demonstrated by the following figure:
Printer setup After STL files have been produced, they can be imported into the 3D printer interface software. The Makerbot Replicator 2X was used to print several prototype pieces for this project, and will be the focus of this section. The Replicator 2X uses the Makerbot Desktop as its user interface software, which will be briefly outlined below. To begin the printing process, import the appropriate STL files by clicking Add File. The size and orientation of the STL can be manipulated using the buttons on the left-hand side of the screen. The print settings can be manipulated by opening the settings menu, located next to the import button. The status of the printer can be displayed by clicking on the monitor button at the bottom left of the desktop. After all settings are adjusted, click on the Print button to begin printing. The process is demonstrated by the following figures.
Trial and error is often necessary to obtain the optimal printer settings for different print jobs. The prototype pieces for this project were printed at an extruder temperature of 240 C, standard extrusion speeds, and with a diamond infill pattern. Post Print Treatment The only post print treatment involved with this project is the removal of excess material. If the piece was printed on a raft, it should be removed along with any breakaway support. If dissolvable filament was used for the support material, it should be allowed to soak for several hours. A small amount of force may be required to help break loose and dissolve the support material inside of the hinges. Brace Assembly Prior to assembly, all components should be examined for defects. If all parts are of satisfactory quality, apply a light layer of adhesive to the connector posts and firmly push the joints together. Apply pressure to each joint for several minutes, until set. After initial bonding, allow the joints to cure for 24 hours before applying forces to the brace. ABS cement or a similar type of plastic resin is recommended as the bonding agent for best results. Supplementary Components