Large format CNC (Computer Controlled Machining)¶
This week
Computer Numerical Control¶
CNC manufacturing is a process using computer numerical control - CNC machines. CNC machines are tools such as mils and lathes guided by computer instructions that control the precision of the instrument.
Guidelines¶
Safety¶
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Wear closed toed shoes during all cutting sessions.
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Avoid wearing loose arm clothing and dangling jewelry.
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Keep long hair tied and hijab tucked in.
Stop the Machine¶
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Punch the red button on the right side of the machine.
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Controlled box.
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Pause the machine by clicking on any key on the keyboard.
V-Carve Pro¶
VCarve Pro provides a software solution for cutting parts on CNC machine. As it is mentioned in the VCarve Website “VCarve Pro brings the third dimension under your control with the ability to import and toolpath a single 3D model. With unlimited job and toolpath size, true shape nesting & job set-up sheets.” It is a very useful and powerful tool, and highly needed for CNC printing.
Joints¶
There are different types of joints that can be used in a design. This guideline will help you with few types of them.
Easy steps towards creating finger joints on your model.
Execute¶
Test¶
We are required to design something to test some of the features of V-Carve as a group, and to get familiar with the machine. For the design we wanted to go for something useful and needed by us. That thing would be a Mold box for our other project. Since the volume we are working with equals 175.2066271 cm3; the dimensions are calculated precisely and then used in the designing process.
For more details about the PP project, click on the projects section above!
The design files are then opened in VCarve software to fix any possible errors on the design, specify the sheet’s size, the type of cut.. etc.
When executing the design, the wooden sheet needs to be fixed by screws in order to avoid wrong cutting that could happen due to the sheet moving. For that purpose, we must leave a margin in the corners when fixing our designs on the sheet in the software; to avoid hitting the screws.
As for the sheet size, we are working with 12mm thickness. When introducing the thickness to the software, we advise to add 1 mm to the existing sheet thickness in order to reduce the errors of imperfect cutting. You may wonder How do we add 1 mm when the existing sheet is only 12 mm? What are we cutting 1 mm of? We do so by adding an extra sheet below our targeted sheet called sacrifice sheet.
Lastly, taps should be added to the design whenever required. Adding taps improve the efficiency of cutting. Don’t worry! The taps can be easily removed later.
For our testing design, we are using screws instead of joints. But if you are using joints, you need to specify each joint’s type in the software, and the type of cut whether in, on or out. Generally, for design cutting we use outside, and for joints cutting we use inside.
Specs¶
runout & alignment
The alignment was confirmed to be okay when cutting the design as the squares turned out perfect and there was minimal runout
speeds, feeds
Speed found to be the best was 17000 RPM and 100 inches per minute feedrate and 15 inches per minute plunge