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® 300Smooth-Cast™ 325Smooth-Cast® 320
Product Type
  • Urethane Resins
  • Urethane Resins
  • Urethane Resins
Mixed Viscosity80 cps100 cps80 cps
Mix Ratio By Volume1A:1B1A:1B1A:1B
Mix Ratio By Weight100A:90B115A:100B100A:90B
Pot Life3 minutes2.5 minutes3 minutes
Cure Time10 minutes10 minutes10 minutes
Shore D Hardness707270
Specific Gravity1.05 g/cc1.07 g/cc1.05 g/cc
Specific Volume26.4 cu. in./lb.25.9 cu. in./lb.26.4 cu. in./lb.
ColorWhiteClear AmberOff White
Tensile Strength3,000 psi3,170 psi3,000 psi
Tensile Modulus139,500 psi140,000 psi138,000 psi
Elongation @ Break5 %10 %10 %
Compressive Strength4,000 psi3,500 psi3,650 psi
Compressive Modulus45,800 psi36,500 psi45,800 psi
Flexural Strength4,510 psi3,690 psi4,500 psi
Flexural Modulus128,000 psi101,000 psi132,000 psi
Shrinkage0.01 in. / in.0.01 in. / in.0.01 in. / in.
Heat Deflection Temp120 °F120 °F140 °F

Rhino 3dm

Fusion 360

Designs, CNC File- All Files