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6. Molding and Casting

My goal this week is to: - Design appropriate objects within the limitations of 3 axis machining - Demonstrate workflows used in mould design, construction and casting

Group Assignment

We did a group assignment to learn about the materials that can be used for molding and casting, details like the name, picture, safety, procedure to follow, details concerning the materials and everything else was put in This page

Individual Assignment

The requirements for the design size are as follows: - Smallest gap: 1.6mm (That’s the smallest milling bit) - Design height max: 8mm - Design width and length max: 60mm The design is 2.5D, as in we shouldn’t be able to cut it using the laser cutter.

Using the skills learned in week 2, I made a design that follows the requirements using Fusion 360

Design steps:

  • Create a rect sketch
  • extrude rect
  • fillet rect
  • cut to shrink design
  • create a circle and cut inside
  • create text sketch and then extrude

  • scale times 10 to match design max height and length

  • fillet inner side

Resultant Design:

Milling the design

The design I created will be milled using the monoFab SRM-20, we did the milling in pairs, so it was necessary to use tinkercad to put both designs together in one file.

We will use SRP-player to mill the designs, the X and Y coordinates were swapped, so we changed the rotation to 90 degrees to fix the coordinates.

Then we chose the type of milling settings we want.

Afterwards, we chose the working material, then measured the length and width of the board we will use, and put the measurements accordingly, then went for “create tool path” option.

This is how the resulting product looks like We wanted to put a wall between both designs, so we returned to “create tool path”, made a copy of the files, and then proceeded to edit them accordingly.

I went to the rough and finished files, chose partial, and focused each file on our design individually. This is how the finished product looks like after modification

The machine had chosen for us a 3/32 tool, but for my friend, he had to choose different settings, the roughing will use 3/32 tool, and the finishing will use 1/16 tool, while I will use 3/32 for both roughing and finishing.

now we are done with the settings and will go through the procedure of starting the machine.

We have replaced the tool that was used for surfacing in the spindle with the 3/32 tool, and then we confirmed in the setting. We will now adjust the position of the spindle, such that it is in the origin, and is barely touching the ground, for this we will use an application called VPanel for SRM-20.

to begin, we will go to the move section, origin, and then click X/Y to return both XY positions to the origin.

Now we will look for the origin point we want for the Z coordinate, for that we will be adjusting the step to be per 1mm, and then we will be decreasing the Z coordinate until the end point.

After reaching a certain point, we started the spindle so that we will know if it reached the surface or not, we needed to decrease it further.

We reached the point we want, now we go to “set origin point” and click at Z, now we have the origin point.

now we have completed all the procedure and will start milling, the milling time is 1 hour and 10 minutes separated into 4 parts.

this is how the finished product looks like

After the milling is complete, we clean the finished product, and then put silicon rubber in it.

Procedure to put silicon rubber:

  • put finished product in the scaler
  • Zero the scaler
  • Put water until you barely fill the product
  • note down the measured number
  • use the measured number to put the ratio 1:1 for A and B
  • Pour the Part A and B together, then stir the silicone rubber for about 3 minutes, then put the silicon rubber in another pot, and stir again for 3 minutes
  • pour the finished silicone rubber in the finished product

Now we check the finished product, and remove it if possible, then we wait until the next day for it to completely dry

Casting in finished product

Now we will use the material resin along with some color material to pour it in the finished product

Process steps: Step 1 : Purchase the required materials and put on your personal protective equipment. Step 2 : Mix the resin and hardener in the suitable ratio (10:6) Step 3 : Add pigments or colours to it. (black) Step 4 : Pour it in the mold. Step 5 : Cover it. Step 6 : Let it dry.

removing the surfacing bubbles from the casting improves the structural integrity of the final product. Bubbles can create weak spots and defects, and can lead to an unsightly appearance.

Last update: August 8, 2024