In 2016, 3 of our students at Howest developed a box of storage of earplugs which can be mounted onto a walking stick. This year we have further optimised and digitally adapted the design for universal use. People can easily use our product by following a short training digitally customized to their needs. By doing so we can tailor the different parts to the requirements of our clients.
A second innovation of the design is the optimised magnetic hinge. Previously we used a classic pin joint, which proved not to be very durable. Therefore we improved our product by using a magnetic hinge. The magnetic hinge has the benefit of being much more durable as well as easy to repair without further damaging the box.
Thirdly we made an advanced prototype optimised for injection molding. This way the product can lead to a larger mass production. The measurements of the mold can be adapted to the user needs. Afterwards we create a test mold with these customized measurements. The last step of this testing process is the extrusion off different prototypes by using different materials.
Step 1: Tools and Programs
This project is divided into two parts. First, we have optimized the original design by adding a magnetic hinge.
Second, we have optimized the product for injection molding. Both are explained below.
Depending on the choice of reproduction of the product, 3D printing or injection molding, you have a different list of requirements.
What you need? You can find a PDF with the needed parts (whatyouneed.PDF).
The necessary STL files for 3D printing, you can choose to use standard variations. The four variations available are key box, USB box, ear plugs box and eye drop box with a diameter ∅25.5. Or you can customize your own box by adjusting the paramters. How to do this is explained in the next step.
If you want to produce a box by injection molding, first read the requirements carefully. Below you can find all necessary files.
Step 2: Adjusting Parameters
If you do not find a suitable variation for clicking on your walking stick or bicycle, you can adjust the parameters and build up your own box. Before you can do this, it is important to know what the parameters are. These are the diameters of your tube material, the height, length and width of your object that must fit in the box.
Once these have been measured, you can enter the parameters in Siemen NX by following the manual. This manual can be downloaded below.
Step 3: Producing
Now that all files have been collected and adjusted, you can start making the product.
For 3D printing, look for a fablab, a friend or order it. A handy link can be a 3D hub, here you can search for someone with a 3D printer and send your file. (link: https://www.3dhubs.com/3d-printing)
Milling the aluminum mold is a bit more complicated. If you use the programmed fusion files, you can immediately look for a fablab with a CNC machine or use the service on 3D hub, which can also mill molds. link(https://www.3dhubs.com/cnc-machining)
Do a final check with the person operating the machine.
In total you need 3 pieces of aluminum, the dimensions are: 1. 2 times 110x60x30mm 2. 1 time 80x40x40mm
Milling the aluminum mold is a bit more complicated. If you use the programmed fusion files, you can immediately look for a fablab with a CNC machine or use the service on 3D hub, which can also mill molds.If you do not use the fusion files, you will first have to re-load your file from the template into fusion and program which actions with the appropriate milling heads are needed.
If you do not use the fusion files, you will first have to re-load your file from the template into fusion and program which actions with the appropriate milling heads are needed.
Step 4: Result Milling
After a few hours your cavities should be ready, and you can start with injection molding.
Here the result after milling the mold. You see that the complete mold consists of 3 pieces
Step 5: Injection Molding: Do's and Dont's
What you need:
- granulate (own choice, we have used PP)
- cutter knife
- duct tape
- wire cutter
- wooden boards
- injection molding machine
How to do it?
Step 1: Find the viscous temperature of your plastic.
Step 2: Turn the machine on and set the correct temperature. Let the machine warm up.
Step 3: Place the mold in the machine, pay attention because the nozzle is very hot. Use piece of residual wood to place the mold at the correct height
Step 6: Injection Moulding the Part
After placing the mold, and the machine is warmed up. You can start with injection molding. Center the mold with the nozzle. Close the safety cover. Insert the granulate at the top. Move the handle slowly down, you will hear the plastic inject. Now you wait until you see the tube no longer drop, then the mold is full, and you can bring the handle back up. Allow the mold to cool sufficiently, afterwards you can remove the injection molding.