Computer Controlled Cutting

Computer Controlled Cutting

By Saheen Palayi | 11 February 2021 | FAB Academy 2021

week 3 group assignment is to characterize our lasercutter's focus, power, speed, rate, kerf, joint clearance and types

Overview

So this week we are gonna design and make 2D objects by using cutting machines.Mainly focused on Vinal cutting and Laser cutting process. So with the the help of the instructors we Learned about the machines that we are gonna use this week.

Laser Cutting

Laser cutting is a type of thermal cutting process which use a focused laser beam in the cutting area to melt the material and then a gas or Air used to eject the molten material for making it cut.


laser-cutting-process
From open.edu article

The above figure shows a basic components of the laser cutting machine's nozzle. The machine is based on a 2 axis CNC it will have two motors to drive each access according to the given x,y coordinates. Laser machines are widely using today we can see them near by Acrylic or wood working shops. They available in different shapes and different power that totally depends the material being used to the cutting process.

Trotec Speedy100

In Our FAB LAB we have two different types of Laser cutting machines.One is used for the FAB academy it can Cut Acrylic,wood,cardboard...etc. The other one is Fiber laser cutting machine part of the Super Fab Lab It can engrave circuits to make PCB. Both are manufactures by same company But,little more power full than the other one


laser-cutter

In the figure shows the Laser cutting machine setup from Trotec using in our LAB Mainly it has two component one tis the Trotec Speedy100 CO2 laser cutting Machine and another one is a Fume extractor & Filter which connected to the Laser cutting machine. It helps to extract the fumes which creates during the process then it filter the fumes to remove the carbon contents


laser-cutter

The other machine at the super Fablab named Speedy400 quit powerful than the speedy100 as shown in above and also have larger work area


laser-cutter

These are the main user components to aware the Transparent lid and inside a hexagonal mesh bed ,moving laser head,control panel etc..


laser-cutter

This is the control panel for users to move the laser head for selecting the work area. And also some other controls as well to control FAN ,pausing controls,z axis bed leveling control etc..


laser-cutter

To cut different thick material the laser head and the work needs to be in focus distance.This tool is the focus distance of the speedy-100-laser machine. We have to set the focus manually for each different thick material

Kerf of the laser cutter

like I said laser cutting is a kind of burning process. So, burning melt the material which cause shrinkage and material loosing effect on the cutting material. this phenomena will effect the end results.So, we should adjust the loosing measurements in the design and that is called kerf.


laser-cutter

We created a vector file of a 20 mm square inside a 40 square in Inkscape .The test is all about measuring the square inside the 40 mm square without Inside Fill and find out how much the width of the laser beam passing line.Then changes it's stroke color to proper RED and Stroke style width to 0.1 mm


laser-cutter

Then we send the file to Trotec interface software from inkscape like we used to print by selecting File >> Print.Then selected the 'Trotec Engraver v10.4.0' and opened the preference


laser-cutter

In the preference window we can select the material and other properties we are cutting on a cardboard sheet. After selecting updated the setup by clicking the Trotec 'JC' logo button.


laser-cutter

After clicking the print the Trotec software opened automatically with the file


laser-cutter

The softwares shows the dimensions of the Engraver's bed and also shows the material selections and power,speed etc.. On left we can see the file in te job list .So as next step we connected the laser by turning the Engraver's power switch on and then hitting the connect button in the software.It's mandatory to close the lid of the Engraver to complete the intital homing setup.


laser-cutter

After the software made a connection with the speedy100 the pointer which represent the laser head show up on the software's work area.we can manually move and can decide where to cut it also moves in software


laser-cutter

Then we placed a pice of card board on the bed which is smaller than the bed size . And then we rise the bed towards to the laser head using the Z axis bed up-down arrow keys on the control panel.


laser-cutter

When the focus distance were aprox 15-20cm we placed the focus tool on the laser head and continues rise the bed slowly till the tool touches the cardboard


laser-cutter

After the focusing is done we moved the head to origin position manually. A small red color laser dots helps to show the cutting point on the job


laser-cutter

Then we drag the kerf-cutting-file from Jobs section in the Trotec software towards the pointer on the screen


laser-cutter

If we double click on the job we can see and double check the file before cutting.


laser-cutter

This is the Engraver cutting setup the red color is for cutting job. velocity 1 is set for the 3.4 mm cardboard


laser-cutter

we turned on the filter before hit send to cut . Normally the Filter will turn on automatically when we send the file But in our FAB LAB not connected to machine to teach students the importance of the filter



After sending the file the laser head moved to home position and started cut.And it finished in 14 sec (the above video is 2X times faster)


laser-cutter

Then we taken out the laser cut cardboard parts from the bed and measures using a digital vernier caliper


laser-cutter

So we did math decreasing the outer dimension from inner dimension

we also tried out other materials as well 1.8 mm acrylic and 3.83 mm Birch wood and calculated the kerf


laser-cutter

The cutting power of each material is also different all the information according to the material given below

Cutting and Kerf Details:-

Press Fit Test

For making a good joints in laser its good to know the press fit tolerances of each material. To test that we designed a Test jig design in fusion 360.


laser-cutter

The design made with parametric thickness and kerf variables.So we can change the design for any material to check its press fit.


laser-cutter

we created a new sketch on the surface and saved in dxf format to cut in laser


laser-cutter

Then opened each dxf in Inkscape and added measurement details to engrave on top of it.The engraving job kept in black color and cutting kept in red


laser-cutter

Opened each in the Trotec software and setup the engrave settings, then Engraved and cuts them out starting with cardboard


laser-cutter

The engrave speed vary according to the material just like the cutting speed here the cardboard engraved more than other two and the clear acrylic jig is the less visible because of it's material property


laser-cutter

We tested each jig with a pice of material which we cuts for finding kerf and found the press-fit values

Engraving and Press-Fit Details:-

Back to top