Messages

491

Show"N"Tell ( Your Machines) / Re: My new project

« on: January 03, 2010, 11:08:48 PM »

Temp shows 18 here in TN, as of now (11:00 PM).  I wish those canucks would keep their cold fronts from crossing the border. Anything below 55 and I'm ready to get the hot cocoa out. I absolutely hate the cold.

492

Show"N"Tell ( Your Machines) / Re: My new project

« on: January 03, 2010, 09:51:24 PM »

Wow. That is indeed a clean shop. Mine looks like the city trash dump. I don't see how you get around without the proper obstacles to trip over.

493

General Mach Discussion / Re: router tooling

« on: January 03, 2010, 03:22:38 AM »

Thank you for replying back. Glad to help out. I can tell you from my own experience, that I'm glad I started with a router build, and not a mill build first. That way, you find out the majority of the mistakes, and the "wish I woulda done it this way instead of that". I would rather have a second rate router than a second rate mill. Routers are more forgiving. Good Luck!!

494

G-Code, CAD, and CAM discussions / Re: gcode mastercam offset question

« on: January 02, 2010, 07:58:09 PM »

been there, done that.

495

General Mach Discussion / Re: router tooling

« on: January 02, 2010, 09:20:04 AM »

Tweakie: That's indeed true on that particular style of cutter, however, there are also "center cutting" endmills that go across the entire face for plunging. Most of the carbide cutters are center cutting, at least the ones I'm used to having.

496

General Mach Discussion / Re: router tooling

« on: January 02, 2010, 09:09:43 AM »

Not sure exactly what video your referring to, but most carbide cutters can be used successfully on wood as well as metal.

WARNING: Rambling below....

 The thing about having a machine for both metal and wood is that the spindle speeds are so radically different for the two. The tooling may be the same, but the spindles are vastly different. The spindles that do cover a broader range cost a premium, and even then, they don't cover enough of the range to be really considered "dual purpose". When I think of speeds, I think 60-2500 rpm for metals, 12,000-30,000 for wood. Most people build their machine for either wood or metal, not both. You can cut metal with a high speed spindle or router for wood, but it has many drawbacks, and you shouldn't expect near the results you achieve with a milling machine. Some people have more than one spindle. If you make a simple attachment for a router, you now have a suitable secondary spindle for wood. The same goes for high speed engravers. Most of the wood guys have an attachment for those too. Also, keep in mind that if your going to be cutting metal, the rigidity of the machine needs to be far far far more stable, than for wood. Any flex at all, and you get broken cutters on the tips. After that happens....well, you've got years of machining experience to know what happens when using dull or broken cutters. This extra rigidity equates to a much higher price in the machine build.

I know I went into more than what you asked for, but you stated that you have years of machining experience, so naturally I'm thinking you want to achieve results close to what your used to with metal working machines. You also state your plans for a spindle, which tells me that your building, rather than retrofitting. You also state that you want to cut wood. This raised an eyebrow, and I felt some common misconceptions needed to be, at least, brought up.   With a bit (tons) of research and a little (a lot) care in design, you can achieve a machine capable of cutting both wood and metal, but it's not really possible to get both without some versatility. I'm not trying to dissuade you in any form or fashion, just a friendly "heads up" from my personal opinions. Take it with a grain of salt. When you start your build, keep us posted with pics and such. We feed on pics like a cow in a field. Can't get enough!

497

G-Code, CAD, and CAM discussions / Re: gcode mastercam offset question

« on: January 01, 2010, 04:33:43 PM »

only thing I can think is maybe mach 3 is trying to do a cutter comp too?

No. There is no cutter comp in the code.

for a smaller cutter the other direction?

I know what your saying. Comped to the inside instead of the outside. Not possible, because there is no cutter comp in the code.
If you do a single step through the code, you can see that Mach is telling the machine the correct points to go to. The circle starts at X -1.25, and 180 degrees later is indeed at X +1.25. This is what your seeing too, correct?
If you say that your machine travels 10 inches when you tell it to, and your using a half inch cutter, the only other option that I can think of that would cause the problem is that you have it scaled down in Mach. The "scale" LED's are not flashing, are they?

498

General Mach Discussion / Re: Mach Controls On/Off of spindle, not speed?

« on: January 01, 2010, 02:43:20 PM »

Do you commonly change the speed of something mid job?

pretty much 90% of the time.

How does your CAM software know when to insert a speed change?

Some CAM software calculates the chip load and all that stuff for you, so it will output the correct (recommended) feeds and speeds, based on the tool selection, like Russ stated.  Some will even make changes for arcs and other stuff. The parameters can really get advanced with high speed machining. The way my CAM tells what feed and speeds to use are....by me telling it what to use. Just from experience. This usually gets it in the ball field, or at least inside the stadium. Then I can use the overrides to dial it in. If I have several parts to cut, I go back and edit the feed in the code to what it needs to be.

isn't having it external preferred, so you can adjust on the fly if need be

Preferred may be a bad way of looking at it. More suitable would be...ability to control externally.

Is there an advantage to controlling the speed through Mach3?

Absolutely. Say for instance you run a large quantity of parts, that require changes in speed for different tools. You wouldn't want to have to change the speeds and feeds manually for every tool change, for every part.

499

Show"N"Tell ( Your Machines) / Re: Dixie Duke - A machine in the making.

« on: January 01, 2010, 02:16:46 PM »

HAHA! Hard to do when their waving cash in front of my eyes. I'll take all I can get right now.
Your correct Rich, it always takes longer than what was planned. Especially since the CNC mill took a bullet to the head. That REALLY put a damper on my project. Everything can still be done on the manual mill, but at a much greater expense of time. Discouraging to say the least.

500

G-Code, CAD, and CAM discussions / Re: gcode mastercam offset question

« on: January 01, 2010, 01:48:35 PM »

You are correct, you should get a 1.5" circle if you programmed a 2" circle and cut it with a .5" cutter. Lets take out the comments in the file to have an easier look at it. There is not a cutter comp called in the code. The circle is 2.5" as coded , not 2" with comp on. If you cut it with a .5" cutter, you should get a 2" circle. You say that your getting a 1.75" circle though, so something is still wrong. You say that your steps are set correctly and the machine does truly move the commanded distance when told.The only thing I can think of that might give you a 1.75" circle would be that your using a larger cutter instead of a .5" cutter. Maybe someone else can chime in with a better explanation, and enlighten both of us. As for a note on the cutter comp...It is being modified in the newer version of Mach. I do not know the specifics on the changes, I'm sure there is a post somewhere here going into detail about comp. Sorry I can't be of any more help to you in that regard.

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O0000
N100 G00 G17 G20 G40 G49 G80 G90
N104 T1 M06
N110 G00 Z.1
N112 G00 X-2.25 Y.5 S1069 M03
N114 G01 Z-.1 F30.
N116 X-1.75
N118 G02 X-1.25 Y0. I0. J-.5
N120 G03 I1.25 J0.
N122 G02 X-1.75 Y-.5 I-.5 J0.
N124 G01 X-2.25
N126 Z0.
N128 M05
N130 G90
N132 M30
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