| The Fundamentals |
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| Tips, Tricks and Techniques |
| Written by Ron Branch |
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Setting up the Machine Tool and using good manufacturing practices are just as important as writing a good program. Ron Branch points out the importance of the fundamentals in this excellent article on machine setup.
reprinted with permission The setting up, on machine tools seems to be a lost art these days. Most people get in such a hurry to get something going they forget the basics. It is just like building a house you cannot build the roof without first building the foundation and the walls. Setting up machine tools to manufacture a part, is the same. Years ago I had all of my men give me lists of what they thought were the top ten things you should do when setting up a CNC Milling Center and what to watch out for. The following list is what I took from that, and things I think are important to do, to be good at doing this job. Like any job you do it is important to do it with responsibility, thought, and with pride. 1: Make sure the machine is cleaned out and all the coolant passages are free of chips. 2: Make sure the table is clean and free of burrs. Use your bare hand to check for nicks or high spots and use a Fine Stone to lightly stone them down.
3: Before placing a vise on the CNC table check the bottom of the vise for nicks, burrs, and high spots. Again use your bare hand to check to make sure it is ready if any are present use a Fine Stone and lightly Stone them down.
4: When you place the vise on the table use care not to nick up the table. Check the feel and the vise should glide across the table and feel smooth as you place on the table top.
5: Use the proper T-nuts, studs, heavy washers, and flange nuts for the size T-slots on which the vise is being placed on.
6: Visually align the vise to be parallel to the axis in which the direction you want the vise to be used in. Tighten one stud all the way down as the fixed side as the Zero location for the indicator. Then move the indicator over to the Loser side and move to past Zero .001 for every .01 past Zero the vise is. Tighten the lose side and recheck. Most times the vise will be right there if not loosen this side now and move again past zero but this time .0005 and you should be done. I have always indicated a vise this way and always been able to get it done in 3 times or less.
7: I never take for granted the vise is square or flat I always do a quick check to make sure the back vise is Square and the Vise is flat. If the vise is out of square more than .0002 over 6 inches you part will be .001 out of square and every operation from there will reflect that. The same goes for the flatness of the vise for every .001 out of flat this will translate through further operations.
8: When using parallels check the make sure they are free of burrs and allow the part to sit correctly in the vise. When putting a part in the vise, make sure the parallels do not move. This mean the part is not sitting in the vise correctly. A little trick is use magnets to hold the parallels to the vise jaws or use banding bent to make a flat spring to hold the parallels to the vise jaws. Rubber bands around the outside of the vise to grab the jaws will do a good job as well. When loading parts make sure the parts are free of chips and burrs. This also will affect the tolerance and could scrap a part.
9: Do not over tighten the vise this causes wear and damage to the vise. A Vise is designed to hold a part correctly with the proper length handle. I have seen so many people use a pipe or hammer this is not a good thing to do to the vise. This action springs the jaws and affects the capability to hold and make a good part.
10. Loading tools in the machine is just as important as putting the vise and the part or material in the vise. Make sure the correct collet, holder, extension or what every that holds the tools is in good working order. Make sure the taper is clean and free of burrs and nicks. Load the tool taking care of the tool that it does not get damaged as you load it in the spindle. The most over looked thing causing the most problems is checking tools for run out. Put an indicator against the tool near the holder and also at the end.
I hope these basic things will be helpful and I see these as important steps to take when setting up a CNC milling center and these really give you the best chance to make good parts and do a good job setting up the machine.
Ron Branch Verisurf    |
Comments (1)
#9
1
Wednesday, 24 September 2008 13:48
Kathryn Nickerson
after placing work piece on parallel's, lightly tighten vise and then use dead blow hammer with one tap to seat part flat on parallel's as you tighten vise.
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