Computer Controlled Machining

 

Assignment:

 


The assignment for this week to make something Big!! using the CNC. The idea I have is making a chair suitable for people to sit in the garden or the park.

 

I am going to use Onhsape in onshape.com for designing my chair and it parts.

 

What is CNC

 

CNC is a Computer Numerical Control in which it is the automation of machine tools using a computer to execute pre designed shape or sequences rather than the traditional way of using lever, hand or wheel for execution.

The CNC module were using is J-Cut 1325b.


The CNC were using in fablab kuwait
 
 



The CNC controll monitor with the emergency switch. I upload the my design into the cnc monitor then i set my spindle to 0.3 rpm and the as shown in the pic monitor have x, y and z coordinate to test the right position to cut the wood.

Designing:

 

As the previous assignments before,I getting the  hang on using the complicated Onshape for designing my chair.

 

At first I started designing my seating area as rectangular shape of 55  cm width and 30 cm hight. Then I made 4 cross shapes to fit the legs to hold the seating area. For the cross section the dimension are 6 cm height and 1.8 cm the width.

 

Note: The limit for thickness is 1.8 cm such the maximum thickness will be for all is 1.8 cm or less.

 

The link of my seating design in Onshape.com

https://cad.onshape.com/documents/de1be7b8299d54f69aab400e/w/401eab25219713c4287f7139/e/1d044566fa314b2ad37629a0

 

The seating area with my name done on onshape.

 

 

For the cross shape I need to two parts and like a puzzle fit them together and then assembly them into on shape. The first part for my legs is I made a u shape with 35cm height with 5.4 width  so that when assembled the seat can have the proper support and the chair is done.

 

 

The first piece of the leg is done

 

For the second I made a “M” shape leg to fit the with the first part to create the proper support for the chair.

 

The link.

https://cad.onshape.com/documents/a82ceb0a649dba387b6727a6/w/0eb6da94a0ac49505e1671bb/e/b234f1a8ab5966fa8398b2f7

 

To complete my assembly, the first part of “M” legs is will be connected to the second part which will be “U” shape with the same dimension made as the first leg part to support each other.

 

 

The Second piece of the leg is done

 

 

 

The link https://cad.onshape.com/documents/f3194e881da226d84c414a37/w/61733ad3e51ec7d41d706feb/e/df3c53b3843a200f13d6e0db

 

 

 

 

Cutting:

 

In the cutting phase, I have to save my designs in Onshape by exporting the file in DXF.

 

 

One of my sketches to exported to DXF       

 

 

 

After finishing the DXF I have to convert the file to “Artcam” so that the CNC can read the  file.

 

The uploading the my designs in Artcam I set the following parameters in  the program:

Our CNC settings :
1) Tool type end mill
2) Diameter 3 mm
3) Steover 1.2 mm
4) Stepdown 3 mm
5) Feed rate 75 mm/sec
6)spindle speed 15,000 rpm
7) Plunge rate 50 mm/sec


 

 

 

 

 

converting my design the file to Art cam

 

 

 

    Our CNC machine

 

 

 

 

Note:  The CNC does not work electronically and were waiting for maintenance team to fix.

 

 

 

Artcam file for chair
Leg 1 PLT File
Leg 2 PLT File

 

 

 

 

Changing the the machine

Due to the unexpected circumstances I changed my design dimension innn artcam to fit the CNC limit of 60 X 60 cm. I used the J-cut model 6060 for  my design.

 

The CNC model

 

The dimension for the legs  changed to fit the limit  30 cm by 5.4 cm. The chair dimension changed to 35 cm to 55 cm.

 

 

     

 

  cutting my parts      assembly my parts

 


































seting up the wood for cutting




The result:

 



 

my chaair :)