Flexy-Form Insole - Customizable

thingiverse

I offer a CAD tool that the podiatry profession can implement right at the coal face, or "Chairside" as they like to say. No scanner required. Take measurements, enter values in OpenSCAD or Customizer, export model, print flat and heat form to fit. Open source CAD (OpenSCAD). Customizable insole profile to fit internal shoe size. Thermoformable surface in hot water, re-form time after time. Filaflex and PLA Composite. Print with a single nozzle, material changes with height. Integrated hinge lines. The disclaimer here is that I am only providing information, this is not medically certified and is not designed to be such, but hey in many parts of the world, people walk round on planks of wood or old car tyres so everything is builder beware. Go forth and MAKE!!! EDIT 10/06/2016 : This is pretty much superseded by my software over at http://www.gensole.com http://www.gyrobot.co.ukhttp://www.facebook.com/gyrobotuk Instructions Customizer Parameters The first step is to familiarise yourself with the drawing showing the parameters which define the profile of the insole. These are available to enter into Customizer : Length Heel_Radius Toe_Radius Inside_Width Inside_Length Outside_Width Outside_Length Instep_Offset Entering valid values for these will define the profile of the insole. All of the following entries will turn on/off features of the insole: Foot Pretty sure this one is self explanatory, Left or Right. Note: The insole is designed and printed upside down so please bear this in mind. STL_Type has 3 values, "Joined", "Upper" and "Lower". This means you have the choice of rendering the model into it's constituent models in-case your slicer prefers separate STL's (S3D, Slic3r, Cura etc) or modifier meshes (Slic3r) to vary the infill etc for the different layers. Some slicers, such as Cura have a modify at Z plugin which you may want to use. Use could use dual extrusion too or change filament partway through the model, it's your choice, depending on your printer/slicer, more information below in the "Printing" section. Lattice turns on the Thermoform mesh. I initially thought this might be required but the insole forms well if printed without the little holes, but I left the code in anyway. Number_of_Hinge_Lines This creates breaks in the rigid layers of the insole so it can bend with your foot and shoe. The Joint-Line is created between P3 and P4 and the Hinge-lines are offset from this and they are each spaced 10mm apart. Thickness The total thickness of the insole. Rigid_Layer_Thickness defines how much of the insole is made up of the thermoformable rigid material (PLA). Chamfer_Width Not an exact value in mm but a parameter to control the size of the feather edge around the insole. Because this feather edge is flexible it can be useful to print slightly oversize and the profile will curl up inside the shoe for a good fit. Marking out and Measuring If you have removable insoles already in your shoes then remove them, lay them down flat on a piece of paper or card and trace around the profile so you can take measurements. Another way is to cut out a piece of stiff card so that you can get it to fit nicely inside your shoe and then trace around this onto some paper. You will need to mark on the profile that you have just traced, the points P1 through to P5 which are shown on my drawing. I attach some examples of some Pulman shoe insoles that I traced around and marked up. Draw the datum line of the insole beween P1 and P2 which are points on the extreme ends of the insole that define the length. This will be an important line which will help you measure all the dimensions. Draw lines perpendicular from the central datum line out to points P3,P4 and P5. Mark the centres of the Toe Radius and the Heel Radius on the datum line. Now that all the geometry of the insole is defined, it is time to take the measurements in mm from your marked out drawing. It is easier to take the length measurements along the datum line to the intersecting lines from P3 and P4. Printing There are a variety of options depending on your slicer of choice. Print in flexible material for the lower section on the print bed and PLA for the upper. Note the insole is printed upside down compared to the actual use. Pause at Z height and change the material. You can use dual extrusion for the different materials. The best bond between the materials is achieved if the top shell of the flexible material (e.g. Filaflex) has a solid layer printed and the lower shell of the PLA is also solid. This has the most surface area contact. In fact for strength I would suggest you print the PLA near solid. You can use the following slicer options : Cura - Export the "Joined" stl from customizer and use the Tweak at Z height plugin enabled to change the density of the last layer of Filaflex and upwards to solid. Simplify3D - Export the "Upper" and "Lower" stls from customizer. Import into Simplify3D and slice each stl with separate processes. One low infill density for the Filaflex and high density for the PLA. Slic3r - Export both the "Joined" and "Upper" stl from Customizer. Slice the "Joined" stl with a low density and use the Upper as a "Modifier Mesh" with a higher density. Thermoforming Prepare the recipient by getting them to wear a sock to protect foot from the heat. Thermoforming is a case of heating up a kettle of boiling water and pouring this onto a baking tray with the insole placed on top. After about 20 seconds the PLA will be really soft. Use a spatula, or tongues to remove the insole from the hot water. At this stage best to wear gloves or use a towel placed between your hands and the insole. You can now form the insole to the bottom of the recipients foot. Further Thoughts I want to make the thermoforming process less "skill" based and more reliable so I am reaching out to makers for inspiration that can be implemented cheaply and simply. Some initial ideas: Place insole under recipients foot on top of some foam block, (maybe memory foam), then push down to form insole. Put some rice/lentils etc or dry sand in a shoe box and place the insole on top then stand on it to form.