12. Moulding and Casting¶
Hello!! this week I tried Moulding and casting for the First time and it really went well!
In my molding and casting project, I began by milling a wax block to create a precise mother mold. Once the wax mold was completed, I prepared two silicone molds from it. These silicone molds were then used to cast resin, resulting in the final output. This process ensured accuracy and high-quality replicas from the original design.
This week consists of the following -
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Group Assignment reading datasheet for silicon and resin
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3D file for wax milling
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Wax Milling for making mother mould
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Silicon molds for casting
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Resin casting in silicoon mould
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Group Assignment reading datasheet for silicon and resin
Group Assignment¶
The group assigment was to read the datasheets for casting materials and to compare test casts This we had done on Himanshi Jain’s Page dropping down the website link.
website link Himanshi Jain website
A few takeaways I have from the group assignment is that yes moulding and casting is definetly better than printing because it gives more precision but at the end everything has its upside and a downside, moulding casting really expensive its difficult to do it in masses.
Making of Wax Mould¶
The wax mould that we have prepared is going to be the mother mould so essentially it should a postive mould, I started with thinking what can I make this week and the thought of making a small keychain of a kunai knife which I then Designed myself on fusion 360. This is the file I made in fusion 360.
After making just the kunai knike for the mother mould I had to prepare the file for the wax mould for the wax milling as well so prepared the file for the same. I had to cut the file into half horizontally and make walls on all the sides
Here my 3D modeling for the molding casting was over now I had to actually mill the wax block with my Design file,
Machine that I have used for wax milling is
Roland SRM 20
The sofware we have used for wax milling is SRP Player it is a software dedicated for milling in SRM 20, now I started my process of milling wax
This is the Interface of the SRP Player software, Next I opened the my file in the software.
After adding the file wee need to make sure that the x,y and z all the 3 axis are rightly aligned according to your model, sometimes the orientation of the file changes when we load it on the SRP player.
after we add the file and the orientation is complete we move on to the next step that is to select the type of milling, now this really depends on the 3D model you have. These are my selections for my model to get a better finish.
In this step select the material that you use I have selected wax and it gives you the dimensions of the model that you have loaded in the software, Here just give 2 mm of offset for the clearence and click the create toolpath button.
Here you get options to select the tools for your milling, the machine does milling two times first it does roughing and the it does finishing you slect the roughing tool here I have selected the 8 mm endmill
Here you select you tool for finishing usually a ball tool is used for finishing but the ball tool was broken so we could not use it and selected the 8 mm endmill.
In this the machines creats the toolpath according ti the toolpath that you have selected and then you are ready to previw your file.
Here you get to see the duration of your file and you can actually look at the preview of the milling here.
Once you push start milling it tells you to load the tools, you load the tool on the SRM player.
Set your x, y and z in the V panel for SRM 20 and hit start cutting!
Once you start cutting you get the progress bar of the the milling completion.
Here the milling process has started as shown below!
Making Silicon Molds¶
The silicon mold that I am making is a 2 part mold for my keychain of the kunai knife.
For the silicon mold we got silicon and hardner from a local vendoer and in the proportions 100:1
So for 20gms of silicon we took 5ml of hardner and the we had to mix it really fast because there can be bubbles forming in the silicon. Once the hardner is poured in the silicon we dont have much time quickly mix it fast and pour make sure no bubbles and pour it into your mother mould.
also before pouring the silicon in the mother mould we took the volume of how much silicon we would need by adding the wax shavings itself to get the volume as shown in the image below
after this just poured the silicon into the mother mould
now wait for 12 hours and done! your silicon mold is ready!!!
Hero Shot
Casting!!¶
For the Casting into the silicon mold I choosed epoxy resin to cast and complete my keychain.
we got this resin from a local vendor and the proportions for the resin Epoxy resin and hardner are 2:1, so we too the resin and hardner in the same proportion and mixed it well.
even the resin after the hardner is added we need to whisk very fast so that there is no formation of bubbles
so here I have just taken both of my silicon molds and joined them together and with puuting rubber band on it so that its really tight and the Resin when poured does not seep out of the silicon mold.
This is how I poured the resin into my silicon mould by injecting it through a syringe because after everything was done I realised the hole that I made in my 3D file is really small.
After this just wait for another 12 hours and done!!! you have your final product !!
I also tried making a cast from soldering wire just to try something new.
Here is a picture of how I did it and below is the final picture of the solder cast as well
Some Hero shots for the week¶
