Computer controlled machining


Task to do-

To make something big by using computer controlled machine like shop bot.

What I have done-

I liked this assignment because we have to give only 2D design,machine cut it and our furniture get ready.To make aprototype of solar reflector I made  skeleton of parabolic reflector having dimensions 30cm*122.9538 cm*122.9538 cm by using shop bot. I design this parabola for making prototype of parabolic reflector.This prototype we can use for small scale cooking as it not as much efficient as parabolic reflector prince 40. But if we scale up this model then we can use it for mass cooking.

Procedure-

first of all I read about parabolic reflector and its different model, see about how we can draw parabola in different ways.My instructor francisco suggested me one app in which we have to put depth and diameter of parabola and it calculates its focal length.This software provides 2d curves.I calculated curve in which Focal point will be on the upper surface of parabola.focal point should be on surface because we have to put pot for cooking on that parabola, So it should be easy to put and takeout the pot.We can see 2D image of parabola in that software.I got different values of curve to draw parabola.

Then I have designed this parabola in kokopelli design software by using curve values.I downloaded antimoney by following.Previously I tried to use this software for editting circuit board.For downloading kokopelli I used this link Below in downloading link you can download 3D .stl file


1.I draw parabola and make it hollow in 123d Design software
2.Then I slice it in 123D make software
Did nasting for efficient use of material
3.First I cut that design by using card board sheet by using laser cutter
4.Before sending design to shopbot I give inner and outer path by using vcurve
5.Did settings of shop bot
6.Then I cut it using shop bot
7.And finally I assembled that.

for making 3d object by assembling 2d sheets we have to make parts of that object and have to design that part in 2d .For doing all this 123D is recommended software .Because in this software we need to provide 3d model only.It gives different options for dividing the model in parts.We have to choose that option and it generates 2d designs. We can get designs according to material thickness.

1.making of parabolic design-
We need to take care at the time of making 3d design which we have to convert later in 2d ,
 that means we have to take care that we require hollow thing or solid.




then made it hollow 



It looked like below



2.I sliced it in 123d make.It accepts .stl file and covert it in 2D file
I converted file in .dxf

3.Before going for actual cutting we have to cut its prototype to check whether out design is ok or not.It saves our material.So I used coral draw resize the object for testing.I used cardboard sheet.



By this cutting on cardboard made me sure about the press fit design of shopbot




4.Vcarve settings
I used vcarvepro for assigning tool path either it is inner cut and outer.I used Vcarve pro V8.0 In VcarvePro we have to store file in .sbp format.I import my final design in Vcarve pro(shopbot CAD&CAM software) For CAM(computer aided machine) and Selected profile and used tool 57-900(6.25mm) end mill with 6 steps I used this settings for 6mm plywood sheet cutting.I used this tool to get wide range of speed and feed rate.If we use thick tool then it not gives good combination of speed and feed rate.For cutting genarally we have to use small tool and for milling we have to use strong and thick tool.

Tool selection,Feed rate,spindle speed and plunge rate is depends on
i)which type of material we are using?
ii)Thickness of material
iii)Type of cutting(Through and through or milling?)

I used feed rate 50 mm/sec it is a rate of movement of shopbot bit in xy direction
spindle speed was 9000rpm it is the speed of tool rotation
plunge rate was 25 mm/sec it is a rate of movement of shopbot bit in z direction with this specifications I calculated tool path. selected the different paths and contours to be as pocket and to have 2D profile.
Pocket gives Engraving
2D profile means Cutting




5.Before giving final command to print

i)Remove dust collector hose
ii)Access the tool rack and get the appropriate tool
iii)Get the tool changing spanner
iv)Loose the tool holder by rotating both the spanners in inward direction and remove the tool
v)To load the appropriate tool, use spanners to tight but this time move them outward to tight it
vi)Fix material sheet on shopbot bed.I used clamps to fix the plywood sheet with bed.
vii)Make Z Zero-
This is very important activity.By doing this we inform machine about position of tool with respect to bed surface and machine get idea about how much deep it has to go for cutting or milling.When we give zeroing the z command from software that time software ask to keep metal plate.So we have to put that plate below tool and on the surface of bed.After this tool comes down,makes contact with the plate and goes up.When tool makes contact with plate that time signal goes to software and I think somehow it helps to understand material thickness.


After doing all settings I cut my design on shop bot



 

I assemble its peaces 



and finally parabolic shape get ready


In this assignment I learned to use shopbot,Its settings.Take fun by creating 3D actual model by just providing 2D design.I think in fab inventory we have to include metal cutter which will able to cut metal sheets as shopbot is unable to cut matal sheets

Download files here

You can download all 3D design and app for parabolic reflector
Download all 2D design for parabolic reflector
Download all file for shopbot cutting