10. Molding and casting¶

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

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Molding¶

Molding or moulding (see American and British English spelling differences) is the process of manufacturing by shaping liquid or pliable raw material using a rigid frame called a mold or matrix. This itself may have been made using a pattern or model of the final object.

Typical uses for molded plastics include molded furniture, molded household goods, molded cases, and structural materials.

Casting¶

Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process.

Casting materials are usually metals or various cold setting materials that cure after mixing two or more components together; examples are epoxy, concrete, plaster and clay

What is the difference between molding and casting?¶

Both the processes are closely related or say they are some how one and the same thing.

Both the processes involves pouring of molten metal into a mold/die which will take the shape of cavity mold or die on solidification.

The basic difference between moulding and casting is the method by which molten metal is poured. In moulding the metal is poured under pressure but in casting ut doesn’t requires any external pressure because of low viscosity of metal which facilitate it to move easily under gravitational force.

Moulding also gives you the final product but in case of casting it may not be true and you may obtain unfinished part depending on your final product requirements. (requirement of machining after casting).

Casting use a one time mold but molding can use molds on repetition too.

Molding is cost effective process.

What software i used and why?¶

Rhinoceros is used in processes of computer-aided design (CAD), computer-aided manufacturing (CAM), rapid prototyping, 3D printing and reverse engineering in industries including architecture, industrial design

- Steps :

Start With CAD Design

- Make Close and Solid Model - If Model is open then …Get Error

At ime of exporting select ‘Binary’
If we want to edit gcode then select ‘ASCII’
Binary (Recommended)

- Checking object is close or not, so best thing to check was use “fabmodules.org”. - once it done it give proof that object was closed.

After exporting we can check our model is close or solid ia Fabmodules.....
If Tool path is calculated in fab mods then model is okay.
Now as per machine software has been used.
CNC is preferable. We can also use Roland MDX 20 Milling machine.

Time for CNC¶

Select material : We can use Wax, MDF, PLY, etc as our requirement
From my side i used MDF 12MM Sheet X 4 = 48 MM

Using partwork to generate toolpath for roughing and finishing.

Here everyone using wax, i try wax with my friend but my instructor suggest me to use other material. So, i decided to use MDF.

Now, run the roughing tool part first.

Secondly, starting for smooth part use smoothing toolpart.

- This is how the deap

Safety first

Mold making¶

Make a layer with petroleum jelly
Why petroleum jelly? No mold release is needed for silicone rubber. If you are asking about a release when making a multiple part mold, so rubber doesn’t stick to rubber, vaseline is the stuff. Use a wide, flat brush to apply the vaseline so it is just a film, no streaks. Do this just before you pour the rubber or the vaseline will dry out.

The reason using a mold release is useless is that nothing sticks to silicone rubber. You can put a layer of spray paint in a mold and then pour the material and you’ll see the paint pulls loose by how the paint appears on the casting.

Using OOMOO 30 is chemical which help to make mold substance making substance

OOMOO¶

OOMOO™ is suitable for a variety of art-related and industrial applications including making one and two-piece block molds for sculpture and prototype reproduction, casting plaster, resins and wax. OOMOO™ silicones are also suitable for electrical potting and encapsulation applications.
Store and use material at room temperature (73°F/23°C). Storing material at warmer temperatures will also reduce the usable shelf life of unused material. These products have a limited shelf life and should be used as soon as possible. Premix Parts A and B thoroughly before using.
Stir it well
Put mixture in postive part which mill on CNC
Now wait for 6 hours to convert into solid

its Done

My second mold (Its take 48 hours to cure)

Using smooth on solid stone and gypsum

- Now mold is ready now We can use different casting material.

Different types of material and different quality, and different strength and properties

Datasheet-1 - Documanetation on Smooth onn

Datasheet-2- OOMOO 25 Documenatation

Datasheet-3- POYO putty Documnentation

Casting material comparsion¶

	Smooth-Cast® 300	Smooth-Cast™ 325	Smooth-Cast® 320
Product Type	Urethane Resins	Urethane Resins	Urethane Resins
Mixed Viscosity	80 cps	100 cps	80 cps
Mix Ratio By Volume	1A:1B	1A:1B	1A:1B
Mix Ratio By Weight	100A:90B	115A:100B	100A:90B
Pot Life	3 minutes	2.5 minutes	3 minutes
Cure Time	10 minutes	10 minutes	10 minutes
Shore D Hardness	70	72	70
Specific Gravity	1.05 g/cc	1.07 g/cc	1.05 g/cc
Specific Volume	26.4 cu. in./lb.	25.9 cu. in./lb.	26.4 cu. in./lb.
Color	White	Clear Amber	Off White
Tensile Strength	3,000 psi	3,170 psi	3,000 psi
Tensile Modulus	139,500 psi	140,000 psi	138,000 psi
Elongation @ Break	5 %	10 %	10 %
Compressive Strength	4,000 psi	3,500 psi	3,650 psi
Compressive Modulus	45,800 psi	36,500 psi	45,800 psi
Flexural Strength	4,510 psi	3,690 psi	4,500 psi
Flexural Modulus	128,000 psi	101,000 psi	132,000 psi
Shrinkage	0.01 in. / in.	0.01 in. / in.	0.01 in. / in.
Heat Deflection Temp	120 °F	120 °F	140 °F

Rhino 3dm

Fusion 360

Designs, CNC File- All Files