Messages

971

General Mach Discussion / Re: 5 axis kinematics and coordinate transformation

« on: January 23, 2010, 12:03:50 PM »

I don't know the details of how Mach3 handles the moves, so don't know if a plugin can be made. I DO know that 5 axis kinematics are not supported with Mach3, and I just guess that since all the moves are handled in the trajectory planer, it is unlikely that a plugin would work for this.

Daniel

972

General Mach Discussion / Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?

« on: January 21, 2010, 01:26:49 PM »

I enjoy reading your posts, Simpson.

I don't want to get into a science discussion on a hobby forum, but if you are curious about the coatings, you need to look into how cutting works on a microscopic level.

That's as far into it as I want to get, but it is a fascinating subject with lots of technical information available for those with an interest.

Do you have some link to refer me to, where I could read about all this stuff in more detail?

BTW, I called my tool supplier and asked if they had some cutters with coating for aluminum. The guy there said he never heard of coated cutters for aluminum...  he said that the best results in aluminum are achieved with uncoated cutters and flood cooling.

Daniel

973

General Mach Discussion / Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?

« on: January 21, 2010, 01:16:52 AM »

I'm not sure I buy the sharpness argument, as these coatings are literally a few molecules thick.

May be, but one thing I know is that when you come to metal plating you usually want to avoid sharp corners because the coating doesn't hold on a sharp corner... sure true for anodizing, not sure about other coatings.... could be something to do with this...

But please do compare a coated and uncoated edge for sharpness. I think there is a noticeable difference.

That said, I agree that sharpness and surface smoothness is key to successful soft aluminum cutting, as I commented previously. The primary reason I like the coated cutters is not for higher speed or production longevity, since I can't cut at what would be considered 'high speed' by today's standards and I do prototypes and not production as a rule.

So what is the primary reason you like coated cutters for aluminum?

The caveat with uncoated cutters on aluminum is that you *might* get away with a dry cut  . . . . and you might not. The trouble is the way you find out that you didn't . . . which can get expensive in a hurry.

That's true

something that I find very effective for band saw blades is 'grinder's paste'. This stuff is pretty miraculous at keeping aluminum from sticking to saw blades and grinding belts . . . . . just don't use it for final finishing if you plan to paint the part afterward.

My almuminum supplier always use this pasty thing on their band saws... so you say it's a grinder's paste...

Daniel

974

General Mach Discussion / Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?

« on: January 20, 2010, 03:17:10 PM »

I don't know what you mean when you say "coated carbide", but I've learned that the usual coatings like TiCN, while good for extended tool life, interfere with the flute sharpness. Any coated tool I've seen had a less sharp edge than that of an uncoated tool. For aluminum you certainly want the flut to be as sharp and smooth as possible to reduce the friction and heat. Thus not coated mills are better for aluminum.

Here is a good article http://www.moldmakingtechnology.com/articles/030401.html , see second paragraph from the bottom.

May be you mean other coatings, designed specially for aluminum? That make the surface smooth?

Daniel

975

General Mach Discussion / Re: Sheet MEtal Bending with Mach3

« on: January 18, 2010, 01:23:14 PM »

Koko,

Thanks, I didn't know about the modern 5 axis benders. Those we were working with had only one axis and control of the bend angle by means of the amount of lowering the press, although possible, wasn't used much because of the trial and error involved in acquiring the desired angle - we didn't have control of the press position, it was just a hydraulic press.

And I didn't mean ALL the bends are always 90 degrees. Said that USUALLY they all tend to be 90 degree. More than 90% of what we were doing were 90 degrees bends.

Daniel

976

General Mach Discussion / Re: Sheet MEtal Bending with Mach3

« on: January 18, 2010, 11:09:59 AM »

Sheet metal bending is not like pipe bending. With pipe bending you control the length you want to bend with one axis - pushing the pipe, and then control the bending angle with another axis - a rotating one - a pin rotating around a pivot pin and bends the wire in between. If it is a 3D bender then there will be a third axis as well, that either rotates the wire or the bending mechanism around the wire.

In sheet metal bending you usually "feed" the sheet metal manually against a stop which can be CNC controlled. Once in position you push a pedal and a press comes down with a formed tool and bends the sheet metal against a die at the bottom - underneath the sheet metal. You can't control the bend angle with this. If you need a different angle, which is very rare (all the bends usually 90 degrees) you'd use a suitable die and tool. Thus, with a sheet bender you only control one axis and only in single block mode.

Daniel

977

General Mach Discussion / Re: Lathe Tool Compensation Is there a better way??

« on: January 17, 2010, 01:12:50 PM »

You seem to be moving the goal posts every time you reply


Hood

978

General Mach Discussion / Re: Lathe Tool Compensation Is there a better way??

« on: January 17, 2010, 10:47:10 AM »

Why to set you master tool off the probe? Any reason it could change its position? I was actually more thinking in the way of making a macro to take advantage of the electrical probe and set all the tools automatically with respect to the master tool. You could probably use temporary DROs to store the true position of the master tool before touching off the probe and then touch it off, override the X and Z DROs with say 0,0, and set all the tools with respect to that, then return back the stored true position of the axes - all in a single macro. This way you don't need to reset your master tool each time.

If you do it this way, and considering your machine's repeatability, I think you don't even need to machine the part each time and measure it.

Hope it makes sense...

Daniel  

979

General Mach Discussion / Re: Lathe Tool Compensation Is there a better way??

« on: January 17, 2010, 09:10:06 AM »

I would assume you would use the electric probe as is, without machining it to setup the tool table and then when you're set to machine the part, take a cut and measure it.

Daniel

980

General Mach Discussion / Re: Lathe Tool Compensation Is there a better way??

« on: January 17, 2010, 08:48:30 AM »

Why not make an electronic probe that you can chuck and no need to machine it each time? Still has the drawback that you can't use it if you have a part in the chuck, but at least it'd be semi-automated.

Daniel