CNC MILLING

CNC MILLING

GL Form Manufacturing Lab, photo: Stefan Hörner

University for Applied Arts, Vienna Studio Prof. Lynn Compiled by Nathalie Rinne With special thanks to David Erdman

Rules & Safety guidlines: The mill is only available to people who have been formally introduced to its methods of use. In general, this limits its availability to students who have taken a CNC milling seminar, or an option studio in which CNC milling was explored. Limited, if any, exception may be made on a per-student basis. -IF YOU DO NOT KNOW, ASK! Before starting the job: -Before powing on the router be sure that the spindle is free from the work piece or all other obstacles. -Ensure that the part is securely fastened to the table -Do not wear loose clothes. While running the job: -Operator must be present whenever running a job. (In theory, one should never leave the mill running on its own. If one does, and anything should occur, there may be consequences. In addition, this is not to suggest that one can not go to the restroom, but if one is going for coffee or food, the job should be paused.) -Wear googles at all times. -Keep mouse nearby in case of emergency or stopping. -Vacuum part regularly. -Keep hands away from router and bit while running. -Never reach over the machine while cutter is rotating to measure, only to vacuum. -If a work piece begins to vibrate, or the cutter makes excessive noise, stop cutting immediately. -If damage or injury should occur notify staff immediatly. After the job is done: -Clean off all debris from the table and surrounding area using the vacuum machine. -Empty the vaccum cleaner -Organize all endmills and tools back into their proper location. (All tools have been inventoried and it is the responsibility of the user to inform TA’s of any damaged or missing items.) It is a good idea to develop a consistent method or order of procedures for starting up any job sequence. The following is the suggested order of things which are outlined in this tutorial.

Material selection:

Soft Materials: Foam, Wax Hard Materials: Wood, MDF, Acryl, Plastics (be aware that hard materials need full attention!)

Placing the workpiece on table: One must always place the work piece on the table securing it using double stick tape, clips or suction (avoid suction since it takes too much energy!) Locate it with two square corners and ensure that the work piece will not interfere with the current position of the router of endmills. Remember that the long side of the table correspond to the x axis and the short side to the y axis.

Boot the CNC Milling Machine: Press the CNC Milling Machine POWER ON button (you will find it under the table top)

...and switch on the computer screen. When the screen is booted... Click on >turn power on at the right top corner on the screen and wait until the button turns red saying turn power off HOMING the mill > click on HOME and wait until the button turns green saying HOMED. In addition it can be confirmed by observing the absolute coordinates window noting that it is set 0,0,0. (the mill locates itself in the coordinate system and position itself in the predefined location from which it calculates all NC sequences. ) Ensure that the work piece, tools and any other miscellaneous items are out of the way and clear of the router and the endmill.

Insert your Endmill

(Take care since you can easily cut yourself on the milling bits.) At the end of the router is a shank, into which a endmill collar can be placed. Choose the adequate collar for the endmill you are using. Hand set the endmill collar within the shank (it is mounted once it clicks in) Gently insert endmill into collar. Pay attention to the amount of extension away from the shank and how deep it is mounted into the collar. Using the wrenches secure the shank to the router. (Boys: remember that weaker persons will have to open it again!)

Moving to Origin X,Y,Z: You have already set the origin of your model virtually while working in maya and surfcam. Now you will have to set it physically. It is the 0,0,0 in the coordinate system of your model in maya and surfcam.

The Grid represents your table with the long side being the x-axis and the short side the y-axis. The little circle represents the origin set on the milling table.

Pressing on the arrows allows one to move the mill router over the table in x,y-axis. The big arrows move faster than the small arrows. The middle button MOVE XY TO ORIGIN moves your router back to the origin that you have already set before. There are two ways to set z=0

1. automatic: out the metal board attached at the arbor of the mill on the flat surface of your material. Position the router and the endmill over the metal board using the arrows and >press AUTOSET Z0. The router mill move down slowly until the bit touches the board. It will automatically set z to 0. 2. manual: >move the router and the endmill over your material. >Move slowly the router and the endmill using the arrow down. The small arrow helps you not to run the bit into your material. Get the bit down until it gently touches the top of the material. (using a piece of paper between the workpiece and the bit helps you locating the top of the material precisely.) >press the Z0 button. The green arrow should locate itself where the horizontal bar is located check that Z-M is the material height (-2) that you entered in Surfcam

Load Files: At console: Click >add job to queue> A file selector window will open: select your .gc file out of the folder of the current month. >open Select and mark your file blue in the big square box Click >select as current job It will now appear in its designated little box under current job: Click >job output Job Operation Window will open The job operation window allows one to speed of job and to preview (in plan only) what the mill will do. One must always ensure that the cutting speed is set properly and preview a job twice prior to running.

Preview: Preview the location of the workpiece on the virtual table and check if it is well situated. >press table area in the output window. >press reset to clear the virtual table. >press table area again to double check the preview before starting the job.

Operating: Ensure that the work piece, tools and any other miscellaneous items are out of the way and clear of the router and the endmill. (implements like cutters might be hidden in the dust while milling and unpleasant to find.) Dust vacuum: The dust vacuum must be turned on while milling. Make sure that the part is free of dust during the mill procedure. In the Job Configuration portion of the Output window: >press Spindle Speed ON >press Traverse Speed ON and Cutting Speed ON (start with a low cutting speed press start (The START button will turn the into the STOP button as soon as one has begun a job.) watch router and ensure that it is safe and running according to expectations. Increase the Cutting Speed if everything seems to be running correctly. Foam: up to 200 MDF, Acrylic and Plastics: up to 50

Pausing a job: Where the START button is located one will notice it now reads STOP >press STOP (only if a problem occurs) The router will stop. >press stop Spindle Speed The Spindle will stop rotating. Make adjustments >press resume to go on with the job. One may monitor the progress of the Job Operation window. In addition, if one needs to leave for a longer time it is required that the job is paused. Anyone disobeying this protocol may have their privileges revoked or suspended.

Emergency stop: In case of emergency you have a big red emergency stop button under the mill table. >press emergency stop You will not be able to resume the job after pressing the emergency stop!!!

Shut down: >CLEAN UP >Extract endmill and put away, in its case >Remove collar and put away, in its case >Remove part >Locate router in the center of the table Remove file from queue: >clear (in the output window) >done >switch the red turn power off in the right top corner to turn power on. >file >shutdown >press power button under the mill table top >switch off the screen

DONE...