Task

  1. 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
  2. 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

This week was about molding and casting, after wednesday's Neil's lecture on Thursday our instructor Komal took review of what we have to do in this week and explained us the basic process of molding and casting.on Friday we got Rohaan Rege (Fabian-2018,expert)to guide us.before starting the work it is important to understand the concept of molding & casting

Molding

Molding is a process in which a molten or liquid material is poured into a mold and allowed to set

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

To get some final product by molding and casting method we have to go through some process as
make Positive mold -> negative mold -> positive mold/casting

Group Assignment

Basically we started with reading of "Material Saefty Datasheet" for that we have number of material at vigyan Ashram like Machine Wax,Instamold,hydrostone.epoxy for molding and casting.

We thought that in one week it is very difficult to read all the datasheet so,we split the task in group,for that I made the list material wise and then we have to explain that material safety in next discussion so every one can choose their relevant molding casting material.
Avalaible Materials:-

  • 1. Machining Wax
  • 2. Silicon Rubber
  • 3. Instamold
  • 4. Flexwax
  • 5. Epoxy
  • 6. POP
  • 7. Hydro-stone
  • 8. Rubber Solution
  • 9. Soldering rod

Materials

So I got Instamold

What I studied for use of insta mold flexible temporary mold
  • InstaMold Features: It is a Casting Compound,Non-Toxic & Safe to use it can be use for Craft or fine art
  • Key Benefits:Molds Are ready to Cast in 2 – 12 Minutes ,Multiple Castings per Mold is possible for that just add Water to the insta powder,and it Will Not harm & Safe for Body,It can be used
  • It can be used for Preserving,Body Casting,Historical Reproductions,Antique Molding,Repair Hobby Castings,Jewelry Making,Ice Sculptures

Recipe for insta mold is very simple mentioned on the box by manufacturer we have to just add water in insta mold in the propotion of1:3,then then take the part or body for making mold ,and pour the material in it,it will take time 2 to 12 minutes ,for testing part till I don't used it because available material in lab is expired but I will make it in next 2-3 days.


Flexwax

Flexwax is use for making molds from three dimensional objects by simply melting, brushing it on, and allowing to harden. Molds made with Flexwax can be remelted and used again and again.Flexwax is AP Non-Toxic.
Specification:
This has a low melting wax, while using it make sure the temperature does not exceed 120°F (49°C) at any time.

Hydrostone

Hydro-stone is one of the hardest and strongest gypsum-cement. We are using for casting which produces extremely hard surface. The important thing, always add powder to the water, never the reverse. (Sprinkle the powder into water slowly and evenly.)

For test part me and Pooja designed some small parts like moon and one flower then saved it in .stl file format,then our instructor Komal suggest us to check orientation in meshmixer because sometime we have trouble in orientation in termminal we checked it and adjust the image in top plane

Design

meshmixer view


after designing we have to mill the design on green machine wax before starting we will check machine wax specification

Machinwax specification

We fixed the wax on bed by tape and adjust the milling bit for whole milling wax we used the "Modella"milling machine with round 1/8" bit

  • for milling we open our stl image in terminal
  • Click Make .png
  • select the face which you want to mill
  • Select the tool (1/8 rough cut)&(1/8 finish cut) (1/8"= 0.3175mm)
  • Make path
  • Make RML
  • Now set the tool origin(i.e.xmin & y min,move tool to set origin)
  • Send it,then begin milling

after milling we use moldsil for making the negative mold,this process we did in our microbiology lab,for negative mold making we measure the our mold's volume by water then we have to took same amount of mixture of silicon and hardner so we did some calculation,

  • our mold required 20 ml & 25 ml of water for flower and moon respectively
  • so we took 1:10 and 1:20 ratio of silicon and hardner for flower and moon respectively
  • so for flower we used 11ml of silicon and 9ml of hardner
    • we measure it on weighing machine,as per instructions given on moldsil container we stirr it vigourusly and pour it in macine wax,after stirring pour mixture in mold and kept it on the shaker to remove bubbles,and kept it aside for 7-8 hours,then remove the silicon mold from wax it looks so good as per my expectations

    silicon mold

    silicon mold

    Error:
    Here in flower mold ball end bit can't cut the side part,

    Error

    for casting we decided to use epoxy resin & hydrostone material for that we took same propotion of resin and hardener

    as per silicon and hardener i.e.
  • for flower we used 11ml of silicon and 9ml of hardner
  • and for moon 13.25ml of silicon and 11.25ml of hardner

    • in this propotion we don't get good result

    In next test we use "Hydrostone"it is in powder form ,we read the instructions given on container of hydrostone,there we got information as if you took 100 gm of hydrostone and 65 gm of water,. The important thing, always add powder to the water, never the reverse. (Sprinkle the powder into water slowly and evenly.)

    Indivisual Assignment

    For indivisual assignment I decided that I will make 2 positive molds on Wax then I will pour the silicon rubber and for final product or positive mold I will use different material like bismuth,resin and melted wax.so for this I choose simple design of screw driver in two parts

    design

    mold1

    Mold2

    then edit it in mesh mixture

    Mesh mixer

    then this stl file is load in terminal and set as below





    As per design we have to mill to part having symetry but different resistation hole(hole for proper fixing of negative mold for casting)
    we follow same steps did in group assignment ,making png file ,select bit,make path and send the file here we mille first object in rough cut then we have to give it finish cut,it looks like

    we have to follow same steps for second mold

    It's finish cut look like

    After milling both mold looks like

    Here some part of one mold is broked so, for fixing it I used flex wax

    After milling now time for silicon molding,for this I follwed all safety instructions such as wearing eye glass,handgloves and mask,

    then checked the mass by water weighing the took calculate the propotion I took 1:10 ratio as our previous results were better,but this time I put less 1ml of hardner but made the lot of trouble after 16 hours of pouring silicone was not set, so mold can't come out it was worst looking

    Then again I started with calculation and silicon pouring

    this silicon mold come out well,


    Now ,its time to casting,for casting we have to follow some instruction and proper amount of hydrostone .I got it on the container of hydrostone i.e.

  • Take some normal water,and weight it as 65 gm
  • take hydrostone powder ,100 gm
  • sprinkle powder in water (not reverse) soak for 1-2 min
  • Mix with a 1750rpm drill and mixing blade.
  • Pouring should be smooth and steady into the center of the base of the mold.

    • before pouring the hydrostone I arranged it with wise

    then pour the mixture in it through the space,and keep it aside for 3 hrs.then casting looks

    before pouring the hydrostone I arranged it with wise

    before pouring the hydrostone I arranged it with wise

    I also tried the traditional method of molding i.e.flexwax ,I just pressed the screwdriver in flexwax and pour the silicon in it still it is not set, I will do it when I will get extra time.

    Summary

    • I have learnt to read material saefty datasheet.
    • I have learnt process of molding casting.
    • I learnt the properties of different mold ,cast material their curing time and propotionality of mixture.
    • Process includes positive ,negative and positive moldding steps to get final product.
    • Molding & casting isuseful for mass production.

    Files

    Assignment 9 Assignment 11