Molding & Casting

Assignments

To design a 3D mold, machine it, and cast parts from it

In this week the task was creating a mold. Vipul brief all of how it is to be done. Mold is negative of the object we wish to make. But we had to create mold for creating a mold which is negative of negative. So for making a mold first we have to create a positive model of the object.

Another thing we have take care is the base

I decided to make an holder for MTM board. As we were using the board in our group activity of machine design it was required for mounting the MTM board

Task 1 : Making a Mold for the mold

1. Before starting with actual design I noted the board dimension and were holes are located on paper.






2. Next step was designing the mold for mold using Solid work. Below were the steps followed:
• Step 1 is to design the final product.




Product base





Designing the rods inside which PCB will be inserted





Designing supports for PCB so it is hold a height.Note: This is required as MTM module is a double sided PCB and has components present at both sides



• Now the final job is ready, next task is to design mold for mold around it.




Designing base for the job





Designing the side walls. Ensuring they are taller than the job which will form the mold base.





Inserting MTM label



• To support the PCB at the 4th edge additional support was added.






• Now the design for the mold was ready. Before going ahead with mold creation I decided to 3D print the final job to verify the dimention to ensure PCB will propely fit into it.














• Tried fitting the actual MTM PCB into the 3D printed sample. Dimension were perfect. So went ahead with mold creation.






3. Now as my solid work design was ready and verified so to physically create the object we have decided to use wax brick, I mill the job using milling machine.












Milled wax mould

Task 2 : Making the Mold

1. For this step 1 is of selecting the resin and reading details about it.
2. I was using Mold Max Silicon Rubber compound as the material for my mold










3. There are separate fluids as seen for above picture and are to be mixed in a ratio 100:10 by weight. i.e if 100 grams of compound A then 10 grams of compound B.






4. So for maintaining the ratio I had to weigh the material using weighing scale.
5. Setting zero of weighing scale with glass






6. Taking appropriate weight of material maintaining the ratio 100:10






7. Properly mixing both the material to form uniform fluid.Note: Material should be mixed slowly without formation of bubbles






8. If bubbles are still getting formed they can be bursted using twiser. Fill it completely till the top.
9. Keep it for drying for a day or two. In my case I kept it for 2 days as my job was having an height so it took long to dry.











10. Gentle remove it out.

Task 3 : Making final object using mold

1. So now mold is ready and it is to be used for making object.
2. Again for making the object we have to select resin. I had selected an transparent resin Crystal clear 200. It is a water clear casting resin. It comes in 2 separate bottle and is required to be mixed in proper ratio of 100:90 by weight as seen below.










3. Again weighing scale is required to be used and both liquids are to be mixed slowly but uniformly.






4. Slowly pour the mixture into the mold. Fill it till the top and let it overflow a bit for ease of removal.






5. As my final job contained cylindrial rods for holding PCB, I had to ensure that the mixture properly fills it, for same I made use of small wire.






6. Keep it for drying for around a day. And next day my job was ready to be used.

Output files

Job solid work file

Job STL file