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View Full Version : Need some simple GCode optimized for Sherline machines



jmlarson
09-25-2011, 05:21 PM
Hello:

I have some very simple GCode that I am looking for someone to optimize for me. The GCode was developed in turboCADCAM years ago, and does not take into account the power limitations of my desktop (sherline) machines. I attempted to 'fool' the GCode generator by playing with the speed, feed, and depth of cut parameters, but the only thing I have been successful with is obtaining a lousy surface finish and chewing up bits! Clearly this is not my forte, and unfortunately at the moment I do not have the time to try to figure this out. I am assuming the fix for this is somewhere in the range of 'very quick and easy' to fix, so I don't have a whole lot of $$$ to throw at this.

My expectations are only that the surface finish is good, the tool life increases, and it can be cut on a sherline lathe. Since the part takes less that 5 min to cut, the speed at which the cut occurs is not all that important.

The material is Stainless Steel, and I use carbide tools. I am willing to change the tool / tool-type if that is something that needs to happen as well.

One other problem that happens is that I currently only cut in one direction (but have no problem going to 2 directions), and on the return to set up for the next cut, the bit drags along the workpiece (I am assuming that it is due to the rigidity of the machine relative to the toolpressure required to make the cut).

I currently have 3 pieces that need optimizing - 1 on the lathe and 2 on the mill. I figure start with the lathe since that is the easiest piece and we can go from there.

If you are interested, please sent me your rates. I can provide the code for you to look at if you would like, and any other information you need.

Regards
James aka 'newbie'

bostosh
09-26-2011, 12:46 PM
I would just start over.
remember these are not rigid production machines.

Light cuts max rpm.
Gcode to suit the machine.
Prints?

harryn
10-02-2011, 09:09 AM
A friend gave me a used sherline to play with to learn about lathe work. IMHO, it is designed for brass and acetal, not SS. Basically you just have to run each cut at 0.010 in - at least on mine.

I would just look on craigslist locally and find someone with a real cnc setup rather than spend the money to program it for your sherline.

Fastest1
10-02-2011, 11:24 AM
I too have a Sherline CNC mill. First a cut into SS at .010 is a huge cut. I have problems in aluminum at .005. It is good for wax and plastic. Yes you will see Tryally on YouTube do some amazing things as do a few others. I don't know how they do it and I get frustrated attempting it. My small Dyna which actually has a smaller work envelope will cut .1 at 6 ipm or so with beautiful results. Practice the writing and proving of your code on the Sherline in wax or mdf. Then use a bigger machine especially if you are cutting SS.

Joe S.
10-02-2011, 03:53 PM
SS is rather fussy regarding speed(RPM) and feed, chip load. If you try to use high RPM you will heat the surface and "heat treat" the metal surface and then be virtually unable to cut it with your machine, unless you burn it off with carbide (lots of luck with that on those small machines). Keep your rpm low 40 to 70% of steel and keep your cutter cutting, I would use oil (yes Virgina I know carbide is meant to use dry) and do not make brown/blue chips. The other thing is use the softer grades of stainless, NO 400 series.