Computer Controlled Machining

by Dhruv Saidava

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Fab Academy Tutorials & References

Assignment

Make Something Big

Content

Let's Starting with something small
Tools Used

Pen Stand ( 2D Cutting | 15.6 mm MDF)

Starting with Small to Understand working and function of ShopBot

  1. You need to make a drawing in 2D file save as dxf (its universal format)
  2. Open that file in Partwork 2D.
  3. Now you need to setup margin and location of origin
  4. Open toolpath (right side upper corner)
  5. Different icons are listed
  6. Starting it will ask for Thickness ( Use Vernier )
  7. Select Drill Bit
  8. After that select drawing and give a tool path ( Check it is Out | In | Online ) Because a mistake over here can spoil your material
  9. Then as required set for drawing in you project. ( I set OUT for outer cut and IN for holes )
  10. you will have profile to set and check sequence and its animation
  11. Now export to .sbp file
  12. open Shopbot software
  13. adjust a ( X Y Z )
  14. Follow to matching step below
    15. Important Below Image has a Problem in it (There is no tabs , without out that it can create a problem in cutting and also accident can happen


    Photos of the Process


    Important I made mistake in selection of drill bit I selected ball nose instead of End Mill for cutting

    Select Drill-bit according to your requirement and check with Machine rules for RPM according to Material and Drill bit flute.

    In Part work you can select Path and arrange tool path.
    ImportantAlways do inside cutting first then edge cutting. to avoid displacement of material on bed and add tabs at required distance

    Raw file ready now we can proceed to set XYZ axis.

    Setting X Y Z axis


Working with Shopbot Machine


Put material on flatbed
clamp it or screw it so it become fix



Take Drill bit and check that it is proper then you have to set that
Important Switch off ShopBot while changing Drillbit

Check images for more details.

Drill bit has to be fixed on proper depth in spindle.

So starting with Small I have made a pen stand with different Diameter
It has inner cut and outer cut. Material used is MDF 15.6 mm Thickness

Pen stand is Ready. Now lets make something BIG
Problem Faced
  • You need to research a lot for understanding Joints Bend and cuts
  • Selection of material is very important so discuss with expert or do small cut on samples

Sitting Table

Sitting Table Design


Design in 2D opened in Partwork.
  • Setting Size of Material : 1400 mm x 1200 mm
  • Thickness : 12 mm
  • Origin : x = 0 y = 0
  • Data Scaling : Center Data in Job
  • Units : mm

Checking layout

Adding T Bone to design at joining

Selecting Drill bit for machining

Setting up 2d cutting profile.

Tooling path for cutting.


Machining process with SHOP BOT.

Machining completed ready to assemble


Top View of Assemble Sitting Table

Output


Side view with sitting person.

Some Quick Points

  • Safety is very important while Machining.(use mask and Goggle)
  • Don't Move tool after complementation or stopping of job raise tool by upward from z axis then move ( Beginner usually make this mistake )
  • You can once check your tool path by keeping z axis above the material
  • Always check toolpath and profile sequence before starting your cutting
  • have a check for T bone if you are doing something on press fit
  • Very Important : Check for tool path there should be no clamps or metal screw or bolt. ( It can create a accident and its going to hit 5000+ rpm tool)
  • Plastic clamps are used to avoid accident
  • At Fablab CEPT : Our Instructor has tied Key ( Powering On) with Drill-bit changing tool so Machine is always off condition while changing
  • Drill bit hold should be proper otherwise there is chance of breaking it as vibration will be more if length
  • Always have checklist of safety for yourself and machine both. to avoid delays and accident

Files