Introduction to Moulding and Casting

The first step to do the task of this week in to design a model under the given size limitation.

Then, create the mould using a wax block.

And finally, cast the final product.

Designing the Bookmark

Using Fusion 360 Software

Machining the Wax

To have the model shape

First, we need to machine the design on the 50x120 mm wax block using this machine.

As shown in the figure, I fixed the wax on the working area using double-sided tape to hold it on its place.

I will be using two types of tools, 1/16 for finishing and 1/8 for roughing.

First, the machine will do the roughing process using 1/8" tool. I mounted the tool on its place as the following.

To start machining, I opened the Bookmark design on SRP Player software, and then I imported my design in stl format.

The firts step to use the Software is to check the size and orientation of the object.

As you can see here the design is tilted and not parallel to the origin, so I have to rotate the object to fix with the origin.

And still the problem is not fixed, so I opened another software I found in the device to rotate the obejct called 3D Builder.

Using this device I was able to rotate the object, save it and import it again to SRP Player Software.

And finally, the origin is fixed and the y-axis is parallel to the design.

Then I opened Create Tool Path section, and make sure both tools are choosen.

Then click on Create Toolpath to see the process. As shown on the right hand side of the screen, the machine will start with the roughing process and then finishing.

Then go to Preview Result section to see the result.

*As you can see the estimated time to finish the process is 1.4 hrs.

This panel is used to move the tool and working table, which should be moved up until the tool is touching the top surface of the wax.

Then go to Perform Cutting section and click on Start Cutting, a window will appear to install the tool. Press on Next if the tool is already installed.

Another window will appear to make sure where is the origin of the tool.

And finally, press next and the machine will start operating to do the roughing process.

After the roughing process the machine will stop, a window will appear to remind you of changing the tool to 1/16" tool. This is how the wax looked after the roughing process.

After changing the tool, operate the machine again to do the finishing process.

This is how the wax looked after the finishing process.

The waste material was still there, so I used a brush and water to clean it.

I noticed a scratch on the wax, maybe it was caused by the tool when I was changing it.

A Problem I Faced

After Machining the Wax

After I finished Machining the wax, I found a hole at one end of the block. This hole may caused because of the size of the design, which is really close to the block size.

I can not start the next step, pouring the Silicon, while this hole is existing because the Silicon will leak out.

So I thought of a solution to close that hole, which is using a wood stick to cover the hole. I also used a big caliper to hold stick in its place. This way, the Silicon will solidify and mount to the wood stick.

Pouring the Silicon

into the Wax Block

After fixing the Wax and blocking the hole, I am ready to pour the Silicon.

These are items that I will need to finish this step.

The blue and white substances should be added in equal quantities to create the Silicon.

So, first we need to know the quantity needed to fill the cavity in the wax. To know that, I did a water test, which is simply filling the wax with water and weighing it. And I found that to be 50 grams.

Afterthat, I divided this number by 2 to know the quantity needed from each substance, which is 25 grams approximately.

I used the scale again to add 25 grams of each substance as the following.

After having equal amounts of the two substances, I added them togather in one cup.

Then, I used a wood stick to mix them well. Mixing these substances should be really slow to avoid bubbles formation which will ruin the resulted cast.

Afterthat, I poured the silicon into the cavity using the same stick.

Finally, I used the stick to make sure that the Silicon is equally distributed all over tha cavity.

I left the Silicon Mould in its place to solidify and came to see the result in the next day.

This is the result of the Silicon Mould after solidifying.

I needed to add clay at one end of the Mould, because the Silicon was not filling that area well. So I added this clay, to ensure a safe process when I create the cast.

Casting

Pouring Acrylic into the Mould

At this stage, the Silicon Mould is ready to be used. It can be used to cast any substance. Such as chocolate, ice, and acrylic.

As my design idea was a bookmark, I chooded to cast acrylic because it is hard and can be used as a bookmark.

Pouring acrylic has the same process steps of pouring the silicon. Which are, do the water test, divide the amount needed by 2, use the scale to add equal amount of the substances needed to create the acrylic, and finally mix and pour it into the silicon.

These are the two substances needed to create the arylic.

Here are some informations written on the box that we need to know before doing the acrylic.

As witten on the box, a ratio of 1:1 should be added from both substances, work time is 30-40 minutes before it starts to solidify, and it should be kept for 48 hrs to ensure total solidification of the substance.

Afterthat, I poured the acrylic into the silicon as the following.

For decoration, I used a red color and added a tiny amount and then moved it to create a shape using a wood stick.

Result

of the Bookmark!