mould and casting



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what I learned

Mold and cast select materials by temperature difference

About safty

modeling

First I made by clay and scaned it.


Then reduce polygon by fusion360.


Next I made wall and buttom.To remove smootly,I made taper 5 degrees.


But it was too high, I made again.


milling

Test

I cut using SRM - 20. Because it was my first 3D cutting other than PCB, I made a test cut with styrofoam first so that I could fail.

Setting

Launch SRM player and set the size and orientation of the model.


Set according to the question. For this time I chose "Roughly shake without taking time", "Shape with plain shape", "Cut only on the front side".


Go to the next step and press the edit button to set the tool. I will do it at 4 mm square mill this time.


Material setting. This time I chose the foam material. and Set the size of the material.


The spindle speed was 7000rpm.


Check in preview. Because there was a part that was not well trimmed, I increased the size of the surrounding box part.



fail


I set the origin of the mill as the edge of the material,but the origin on the software side was the middle of the material so it failed. In addition, the length of mill put out from its root was insufficient, the root of mill touched the material and stopped emergency.

I fixed the origin and mill length ( more than 43 mm) then run again.


success



I stopped by rough cutting.

It seemed to be able to work without problems so I made data for production. It is almost the same as last time, but change to "give it finely even if it takes time."


Material also changed to "modeling wax".


The rough cut spindle speed was 7000rpm,milling speed was 1440mm/min.


finish cut spindle speed and milling speed was same as rough cut but cutting amount and pass spacing and finish allowance were more small.


Cutting modeling wax. It took four hours. I think it was better way to shorten the time that cut the model by milling machine and make wall with hand using clay or blocks.


Completion. Cutting traces remain. Because I used a square mill. Because I did not have a ball mill in hand.


Casting

First make a mold with silicon. The material used was PTV 4000.


Weigh A liquid. Preliminarily stir.


Weigh B solution. Preliminarily stir.


Combine the two liquid and mix. It was sticky. Since working time till starting harden is 25 minutes, work calmly.


To pour in. I was worried about bubbles in it.


After 7 hours,I remove it from the mold. Although it was a bit hard but it could be removed without problems.


Because the height of the wall was low, the silicon on the highest part of the model was quite thin and the hole was hanging. It is reinforcing with a copper tape.


For use as a push pin, it is installed so that the push pin can be embedded inside. Keep the support raised so that it does not hit the cast.


Put a sheet so that the desk will not become dirty, prepare all necessary items. Ventilate, work with gloves and masks.


I tried using a release agent. Shake well and paint with brine. Wait three minutes.


I use Urethane.


Brown A liquid.


Transparent B liquid.


Since urethane hardens quickly, I have to work quickly. Mix the two solutions and stir them and pour them into the mold.


It gets hot in several tens of seconds, it gets whitish at a stretch and cures.


Remove the mold from when the heat pulled. The silicone mold was soft and easily removable.


Wax , silicon, urethane.