6. Large format CNC (computer controlled Machining)¶
This week I worked on defining my final project idea and started to getting used to the documentation process.
🐰 Lab Safety When operating heavy machinery, safety is always the number one priority. This is no different when operating a CNC machine. It is crucial that proper safety training is conducted for all operators to avoid any harm to the equipment or the surrounding personnel. Some general safety points are as follows.
- Ensure you have received comprehensive training on the specific CNC machine you’re operating.
- Always wear safety glasses, hearing protection, and appropriate clothing (no loose clothing or jewelry).
- Before operation, inspect the machine for any damage, loose parts, or safety device malfunctions.
- Familiarize yourself with the location and operation of the emergency stop button.
- Keep the work area clean and free of obstructions.
- Ensure a fire extinguisher is readily available.
🐰 Runout Runout is the deviation of a rotating part from its true axis. To test this, the dial indicator is used to measure the radial movement of the tool while rotating. Runout is reduced by tightening or replacing worn tool holders, balance workpieces, and ensuring spindle alignment.
🐰 Alignment Alignment is the accurate positioning of machine components relative to each other. To test this, precision measuring tools like dial indicators and laser alignment systems check for squareness parallelism, and perpendicularity. In this machine specifically, the z-axis alignment is done automatically using the software and a basic plate where once the drill bit strikes the plate, it will close an electrical circuit determining the z-axis alignment. Machine components are to be adjusted, worn parts are to be replaced, and the machine must be recalibrated as needed before the start of any task.
🐰 Fixturing Fixturing refers to the method of holding a workpiece securely during machining. Testing this can be unsafe and should be done carefully or through a simulation to assess the workpiece stability and check for vibrations, chatter, and movement. Usual methods for fixtures are the usage of clamps, industrial adhesives, or simply in this case, drilling the workpiece onto the bed of the CNC machine. Screws are drilled onto each corner as well across the middle to hold the workpiece in place.
🐰 Speeds & Feeds The speed refers to the rotational speed of the cutting tool and the feed rate is the rate at which the tool advances and moves into the material. This is tested by starting with a conservative settings for the speed and feeds then gradually increase while monitoring tool life, surface finish, and chip formation. The speeds and feeds are to be adjusted based on the material, tool geometry, and desired results. For the MDF wood, the optimal speed was the highest speed of 17,000 RPM and the best feed rate was the slowest rate of 60 in/min.
Useful links¶
My Work¶
files¶
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