Computer-controlled cutting
Assignment
Group assignment:
make lasercutter test part(s), varying cutting settings and slot dimensions
Individual assignment:
cut something on the vinylcutter
design, make, and document a parametric press-fit construction kit,
accounting for the lasercutter kerf, which can be assembled in multiple ways
Group assignment:
make lasercutter test part(s), varying cutting settings and slot dimensions
Individual assignment:
cut something on the vinylcutter
design, make, and document a parametric press-fit construction kit,
accounting for the lasercutter kerf, which can be assembled in multiple ways
Group assignment:
Laser cutter test
For the lasercutter test, 2 set of test parts were made.
Each comprising of a male and
a female test piece.
The male tab width was designed to be 20mm.
There were 4 female slot width of 17mm, 18mm,
19mm and 20mm.
Finding.
The 20mm slot width gave a loss fitting, the narrower slots
could not fit the tab at all. from here we can see the step of the slots was too wide.
So in the next test, a step of 0.1mm was used instead, slots of 19.6mm, 19.7mm,
19.8mm and 19.9mm were cut. This time round, the 19.6mm slot width gave a good fit.
The test tab's width when measured with a vernier caliper was 19.66mm.
Individual assignment
Vinyl cutting
The cutting was done on a CAMEO silhouette vinyl cutter, the main setting for vinyl cutter was the blade height, the goal was to set the blade at a position that only the vinyl was fully cut but not its backing sheet.
This was achieved by removing the blade from the holder, then it was placed on the adjusting slot provided, there were numbers on the blade indicating different blade height setting. the the particular vinyl sheet we were using, the setting used was number 2.
Vinyl cutting
The cutting was done on a CAMEO silhouette vinyl cutter, the main setting for vinyl cutter was the blade height, the goal was to set the blade at a position that only the vinyl was fully cut but not its backing sheet.
This was achieved by removing the blade from the holder, then it was placed on the adjusting slot provided, there were numbers on the blade indicating different blade height setting. the the particular vinyl sheet we were using, the setting used was number 2.
Next the silhouette studio software was launched and a test cut pattern was selected
The vinyl sheet was placed on the sticky back sheet. The "load" button on the machine was pressed. Back on the PC's sihouette studio software, "send" button was clicked and the cutting began.
The vinyl sheet was placed on the sticky back sheet. The "load" button on the machine was pressed. Back on the PC's sihouette studio software, "send" button was clicked and the cutting began.
Parametric design and laser cutting
The part was created using Solidworks 2016, it is primary a 3D software but can also be used for 2D sketches. However, Unlike other 2D drawing tools, solidwork is parametic and parameters can be defined and dimensions can be set to be driven.
The initial idea was to use wood as it is an environment friendly material. However due to its non-availabilioty, acrylic was used instead. The first thing was to measure the material thinkness, it was 2.97mm.
Next a drawing with 4 slots of 2.72, 2.74 ,2.76 and 2.78 mm was created to test kerk allowance. (assumming kerk width to be 0.19mm to 0.28mm from experience)
2 pcs of kerf calibration part were produced, after measuring and trial fitting. it was determined that the designed slot size should be 2.74mm to get a good pressed fit. Using a vernier caliper, the slot width was 2.97mm.
The next step was to use Solidworks again to create 2 parametric drawings, a global variable "thi" was set at 2.74mm as the slot width. This number was derived from the kerf calibration done earlier on.
The rest of the slots' width were set to follow the global variable "thi", so if a material of different thickness is used, only the "thi"variable need to be changed.
the variable is in the equation tab as shown in red box.
The first part designed is a disc with 4 slots.
The rest of the slots' width were set to follow the global variable "thi", so if a material of different thickness is used, only the "thi"variable need to be changed.
the variable is in the equation tab as shown in red box.
The first part designed is a disc with 4 slots.
Another rectangular part with slots was also created, both parts were then saved under in IGES or DXF format for laser cutting. IGES file is better as it is vendor neutral.
Cutting the Parts
First load a piece of acrylic material on the work surface, align it to the top left coner.
The IGES file than can be loaded using CoralDraw and adjusted to a optimised print origin.
The power, cutting speed and frequency needs to be set according to the material used.
And the cutting began.
The finished product
First load a piece of acrylic material on the work surface, align it to the top left coner.
The IGES file than can be loaded using CoralDraw and adjusted to a optimised print origin.
The power, cutting speed and frequency needs to be set according to the material used.
And the cutting began.
The finished product
Assembling the parts
Assembly 1: a table Lamp structure
Assembly 2: a handphone cradle
Reflection
Lasercutter is a relatively fast machine. Although it works on flat surface, there are many ingenious ways of using it, such as PCB cutting, folding of acrylic......
Getting lasercutter to cut a rough design is quite straight forward, one only needs to ensure that the power and speed is enough for a through cut.
However to get a precision cut. Characterisation of the machine needs to be carried out, this differs from machine to machine. Even on identical machine with same setting, the cutting reult can be different due to the wear and tear of the laser tube and lense assembly.
This exercise has been a useful journey in understanding the necessary steps to get a good lasercut result.
Lasercutter is a relatively fast machine. Although it works on flat surface, there are many ingenious ways of using it, such as PCB cutting, folding of acrylic......
Getting lasercutter to cut a rough design is quite straight forward, one only needs to ensure that the power and speed is enough for a through cut.
However to get a precision cut. Characterisation of the machine needs to be carried out, this differs from machine to machine. Even on identical machine with same setting, the cutting reult can be different due to the wear and tear of the laser tube and lense assembly.
This exercise has been a useful journey in understanding the necessary steps to get a good lasercut result.