11. Molding and Casting¶

This week :

group assignment: review the safety data sheets for each of your molding and casting materials, then make and compare test casts with each of them

individual assignment: design a mold around the stock and tooling that you’ll be using, mill it (rough cut + (at least) three-axis finish cut), and use it to cast parts

Files to download:

Ramadan Mold STL

materials available in our lab:

Material	Category	Series	Supplier
OOMOO™ 30	Silicone Rubber-Tin Cure	OOMOO™	Smooth-on
OOMOO™ 25	Silicone Rubber-Tin Cure	OOMOO™	Smooth-on
Mold Max™ 60	Silicone Rubber-Tin Cure	Mold Max™	Smooth-on
SORTA-Clear™ 18	Silicone Rubber-Platinum Cure	SORTA-Clear™	Smooth-on
Smooth-Cast® 305	Urethane Resins	Smooth-Cast®	Smooth-on

In our lab we just have [Sorta-Clear] because Oomoo 30/25 is expired

Below I will put more details about Sorta-Clear. Which, I will use it in this week:

SORTA-Clear™
Technical datasheet
Safety datasheet
Food safety technical datasheet

MEASURING AND MIXING :

Before you begin, pre-mix Part B thoroughly.

After dispensing the required amounts of Parts A and B into mixing container, mix thoroughly for 3 minutes making sure that you scrape the sides and bottom of the mixing container several times.

After mixing parts A and B, vacuum degassing is recommended to eliminate any entrapped air.

Vacuum material for 2-3 minutes (29 inches of mercury), making sure that you leave enough room in container for product volume expansion.

POURING”:

For best results, pour your mixture in a single spot at the lowest point of the containment field.

Let the rubber seek its level up and over the model.

A uniform flow will help minimize entrapped air.

The liquid rubber should level off at least 1/2” (1.3 cm) over the highest point of the model surface.

CURING:

Allow the material to cure fully at room temperature (73°F / 23°C) before demolding.

SORTA-Clear™ 18 cures in 24 hours.

Do not cure rubber where temperature is less than 65°F / 18°C.

Time to demold can be reduced with mild heat.

important : Rubber will darken considerably when exposed to heat.

Note : Allow mold to cool to room temperature before handling.

Smooth-On’s Plat Cat™ platinum silicone accelerator can also be used to accelerate Sorta-Clear

Summery:

This week I have designed and mold a “dates” and “Ramadan Stamp”. I made them especially because we, as muslims, we have a month in which we fast, and one of our foods is dates.

Machinable Wax:

In the lab we have 3 sizes of machinable wax (dimensions in cm). This will be used to mill the positive mold of the final product.

For me I have choose 15x15x7.6(cm)

CAD Design with SolidWorks:

I designed two models (Ramadan text, date) and put them inside the wax box then export them as stl

Working with Vcarve:

Firstly, I uploaded the STL file that I have designed it in Solidowks Note: In Vcarce you have to go to Importthen upload the stl .You can’t with open files