WEEK 12 - Molding and Casting

a week like a MOUNTAIN - hard climbing - easy DESCENDING. first 3 days were hectic with designing, cam and machining and later where lazy just waiting for curing of mold and objects.

individual assignment

• design a mold around the process you'll be using, produce it with a smooth surface finish, and use it to cast parts
• extra credit: use more then two mold parts
  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
• compare printing vs machining molds

You can find our group page hereand this week is here

Molding and casting is a process of creating a replica of an object. It involves creating a mold (negative) of the desired shape and then pouring a liquid material (casting material) into the mold to solidify. Once set, the solidified material takes the shape of the mold, resulting in a cast (positive) object

.

Types of Molding and Casting:

There are various molding and casting techniques, each suited for different materials and applications. Here are some common ones:

• Sand Casting: Molten metal is poured into a sand mold.
  
• Injection Molding: Molten plastic is injected into a reusable mold under high pressure.

“injection-molding-process.gif” could not be found.

• Slip Casting: Liquid clay (slip) is poured into a mold and allowed to solidify on the mold walls.

• Lost-wax Casting: A wax model is coated with a ceramic material, then melted out, leaving a mold for molten metal.

“lostwax1.gif” could not be found.

Importance of Molding and Casting:

Molding and casting is a crucial process in many industries due to its versatility and benefits:

• Mass Production: It allows for creating identical copies of an object efficiently and repeatedly.
• Complex Shapes: Molds can capture intricate details, enabling the production of complex shapes.
• Material Variety: A wide range of materials can be cast, from metals and plastics to concrete and resins.
• Customisation: Molds can be designed for specific objects, allowing for customisation.

i have a done a rocket with four fins. i think this design will help me learn effectively about 3d milling .it have four fins which will be a challenge for to mill and cast it. i need to find a process to apply these features.

i have designed this extra fin whcih i am thinking i can 3d print and palce it on mold.because this is not millable vertically as this is not accessible to the bit.

3d print part i need to print

one another challenge i faced is sicne am planning to make this 3d object with a single mold. so i need a slot to allign. how can i do it?

so have give one side of the slot extrude inside , mirrored it and made other side extrude outside.

i added size of machinable wax to the design as stock and put my design as positive in it. for easier cam process

size of machinable wax

onle another chi am planning to make this 3d object with a single mold. so i

this is the most important pART OF MOLDING AND CASTING. WE NEED TO CAM THE CAD MODEL BEFORE MILLING THE MOLD.

GO TO MANUFACTURE

SET YOU CAM SETUP.

set the stock setup

now you need to choose a process to to guide the TOOL PATH in this case is to clear maximum wax from the mold. go to ADAPTIVE clearing which is adaptive in nature.

first adaptive clearing

we can either chhose tool library in fusiion. our fablab have its own library they made we imported it in fusion

our tool library

secondly i changed the bit to 3mm flat to ADDITIONALLY clear wax.

setting for second adaptive clearing

now we have cleared almost all all unwanted wax. i need to flaten tha base. for which i added same 3 mm flat bit.

setting for flaten clearing

now we can head to polishing tool path. i added 3mm ball end bit.

fininshing adaptive clearing setting

now we can scallop to final finishing.

my scallop settings

totoal time showed is 38 minute for 100% speed

you can simulate each toolpath for analysing it

now we need to post the nc PROGRAM. this is the file we feed into the cnc machine.

in post we need to select the machine in which we are machining.

1: select and group the bits we are milling in order
2.post it and save . don't forget to name it one by one.

we are using prototrak rmx with dpm rx2 machine which is a 3-axis cnc machine.

after posting TRANSFER the .gcd file to usb and connect into trak port.

dpm rx2

prototrak rmx

display - from manual

wear SAFETY glasses adn gloves while operating the machine

you can refer [user manual]((https://www.southwesternindustries.com/media/manuals/31550_manual.pdf) for further safety PRECAUTIONs of trak.

first secure the job into the vise

now we need to set tool offset and job offset

tool offset we can do by offsetting with vise and job offset we need to use "edge finder"

set offset. the point at which edge finder miss-allign after ALIGNING is the point of contact

edge finding for x axis

edge finding for y axis

we have to absolute set x and y after edge finding.

you can rotate spindle REVERSE and forward according to bit.

BITS I USED

after LOADING the bit go to tool table for setting its properties

now go to -> prog in/out-> select file and -> go.

you can trak the machining using jog for verification of toolpath and afterward choose cnc milling.

NOW I NEED TO CAST NEGATIVE WITH SILICONE AS SILICONE IS FLEXIBLE AND CAN BE USED WITH RESIN CASTING.

use the developer spray for easier mould removal after settign. spray 2-3 layers.

For mold making and prototyping, we utilized Silicone Rubber RTV 1010, a dual-component silicone rubber. It comprises a silicone rubber base and a curing agent, which must be combined in a precise ratio to initiate the curing process. Initially, we got the ratio wrong, so we had to redo it. The correct ratio we used was 30 ml of curing agent for 1000 ml of silicone.

i took a glass and weigh scale to measure the agents.

i first added water in the mold and poured that water to a glass and marked with a pen.then added the grams value of silicone in the container (considering 1gm = 1ml)

then i added the curing agent according to the ratio of 1000:30
ie, 90 gm :2.7 gm. i adde 2.7 grasm of curing agent in it.

here is the link ration calculator wich used to finf the ratio ratio calculator

then i started mixing . please mix in a way that don't create much bubble. otherwise it will effect the final result. mix slow and do to-and-fro movement to get better result.

After ensuring the correct mixture, we allowed the mold to harden overnight. The next day, I removed the mold from the milled block using pressurized air.

created one more silicone mould doing the same process next day.

i tested THE fit of the SILICONE mould adn it came out great.

testing the fit of silicone mould

For the final casting step, we used Aditya Epoxy Resin 37, which consists of two components: Part A and Part B. These components need to be mixed in a 2:1 ratio. The mixing process was a collaborative effort.

To ensure a bubble-free finish, we used an in-house built vacuum chamber to remove air from the resin after mixing. Once ready, each of us took the required amount. I wanted my piece to be green, so I added a small amount of green dye and some glitter to achieve the desired look.

After pouring the resin into the mould, I left it in a secure place to cure.

you can see this video that there are fins that came . maybe due to over TIGHTENING the .silicone cast
“PXL_20240424_055509898_compressed.mp4” could not be found.
yess. the final result came good even though are some bubbls in fins. i mada rocket model with 4 part fins with some colour infused for looks.

the final result

This week, I am on a journey of analysing everyday objects from a manufacturing perspective. Each item I encountered became a subject of curiosity, prompting me to delve into the various methods behind its creation—be it urethane casting, vacuum casting, die casting, investment casting, or CNC machining. This shift in perspective not only deepened my appreciation for the intricate processes involved but also enhanced my understanding of material properties and production techniques. This analytical approach has been instrumental in refining my project documentation, allowing me to integrate a more comprehensive view of manufacturing technologies.

design files