18. Wildcard week - Waterjet cutting¶
Individual assignment¶
This week I wanted to do something with Aliko Waterjet cutter, that we have in the Machineshop at the University of Oulu. Many thanks to the Machineshop Manager Kasper Hahtonen and machine operator Pasi Heikkinen for their help with the machine.
A waterjet cutter is a tool capable of slicing into metal or other materials using a jet of water at high velocity and pressure, or a mixture of water and an abrasive substance. The cutter is commonly connected to a high-pressure water pump (a local water main does not supply sufficient pressure) where the water is then ejected out of the nozzle, cutting through the material by bombarding it with the stream of high-speed water. Additives in the form of suspended grit or other abrasives, such as garnet and aluminum oxide, can assist in this process. Because the cutting stream can be easily modified, waterjets can be used to cut diverse materials. The accuracy and the power of the jet allows high precision cutting, even for complex shapes. Maximum pressure of the used waterjet cutter is 6000 bar, size of the cutting table is 1500 x 3000 cm. The cutter can cut even 20 cm thick steel.
Design¶
I needed to build a barricade of 12 mm coated plywood (sheet size 1500 x 3000 mm), it is used for outdoor games. I did the design using Fusion 360. The shape was pretty simple, it has several rectangular holes.
The Fusion file had to be saved as dfx, to be able to open it in IGEMS-program, which is needed to prepare the cutting file for the waterjet cutter. In IGEMS the toolpath was defined and the zero-point of the cutting was set. Also used material and the material thickness were defined. There was not plywood available in the list, 3 mm aluminum was used instead. Machine operator experience was a great help with that too. IGEMS provided DNC-file that can be opened with waterjet cutter.
Here are some pictures of IGEMS program file preparation.
After opening the dxf file the zero point was defined:
Then material was selected. There was not plywood in the material list, so instead I used 3 mm aluminum
In the Create Part the cut area and cut holes were selected
Post Processing creates the DNC file, that was saved in the memory stick and brought to the waterjet cutter.
DNC file was opened in waterjet cutter and plywood sheet was set on bed.
File was selected from the list
Zero point was measured and set with the arrows
Speed was set and the safety system with light curtain was turned on. Reference Voltage -light turns on.
Cutting pressure and sand amount was defined
Pump was turned on
And the job was started by pressing Play
Now the cutter is cutting
You can see on the screen how the work is progressing:
Here is the cut piece ready:
Reflection¶
The cutting time was only 5 min and the cutting trace was very good. Preparations took some time, the machine did not open the design file in the first place. We ended up in re-booting the machine. After that everything worked nicely.