Messages

5921

General Mach Discussion / Re: Contouring

« on: August 09, 2008, 02:27:56 PM »

I'll agree with the MeshCAM option. Also a longtime user. Easy to use and works great, with new features being added all the time.

5922

General Mach Discussion / Re: removing mach3 driver

« on: August 09, 2008, 02:26:20 PM »

Right click on My Computer, choose properties. Click the Hardware Tab, and go to device manager. Find the driver and remove it.

5923

General Mach Discussion / Re: Contouring

« on: August 09, 2008, 01:02:36 PM »

Before you think about buying BobCAD/CAM, you should go to CNC Zone and read all the posts from disgruntled customers.

5924

General Mach Discussion / Re: Very basic question about tool diameter compensation

« on: August 09, 2008, 11:01:07 AM »

Here's an S.

G40
M3
G0 Z0.1250
G0 X1.5603 Y4.3285 Z0.1250
G1 X1.5603 Y4.3285 Z-0.1000 F50
G42P0.0625
G1 X1.1250 Y4.2500 Z-0.1000 F150
G3 X1.1250 Y2.0000 Z-0.1000 I0.0000 J-1.1250
G2 X1.1250 Y0.2500 Z-0.1000 I0.0000 J-0.8750
G3 X1.1250 Y0.0000 Z-0.1000 I0.0000 J-0.1250
G3 X1.1250 Y2.2500 Z-0.1000 I0.0000 J1.1250
G2 X1.1250 Y4.0000 Z-0.1000 I0.0000 J0.8750
G3 X1.1250 Y4.2500 Z-0.1000 I0.0000 J0.1250
G2 X1.0000 Y4.3750 Z-0.1000 I0.0000 J0.1250
G40
G1 X1.0000 Y4.6250 Z-0.1000
G0 X1.0000 Y4.6250 Z0.1250
G0 X0 Y0
M5
M30

5925

General Mach Discussion / Re: Very basic question about tool diameter compensation

« on: August 09, 2008, 10:28:12 AM »

- for example if you are cutting a window with the tool on the inside, which with standard bit rotation would probably mean you are cutting round in a clockwise direction, what do you use, and for example (since it says left and right) do you need to alter it when you come down the other side)

Again, I explained it in my previous post, and offered an example for cutting around the outside. Here's one for the inside.

G40
M3
G0 Z0.1250
G0 X0.6391 Y0.7309 Z0.1250
G1 X0.6391 Y0.7309 Z-0.2500 F50
G42P0.25
G1 X0.0000 Y1.5000 Z-0.2500 F150
G1 X0.0000 Y3.0000 Z-0.2500
G1 X3.0000 Y3.0000 Z-0.2500
G1 X3.0000 Y0.0000 Z-0.2500
G1 X0.0000 Y0.0000 Z-0.2500
G1 X0.0000 Y1.9312 Z-0.2500
G40
G1 X0.5000 Y1.9312 Z-0.2500
G0 X0.5000 Y1.9312 Z0.1250
G0 X0 Y0
M5
M30

5926

General Mach Discussion / Re: Very basic question about tool diameter compensation

« on: August 09, 2008, 09:47:12 AM »

Hi, Imagine the cutter is a car with 2 steering wheels, one on the left for turning left and one on the right for turning right.
OK so far.

So you get in your car on the right hand side and drive. You can only turn right hand turns so, eventually if you turn 4 rights you have travelled in a rectangle or square. Which ever compensation you used, right for a hole, left for an island. You did not need to change it.

Now lets say the road is an S shape. The start of the S is a left hand turn so jump over to the left seat of the car and start driving left. You follow the S road until you get to the middle of the S you will see that you will need to turn to the right. To do this you have to stop the car and jump into the right hand seat to turn right.

The point at which you have to jump over to the correct seat in the car is the point at which you need to change the cutter compensation if you want to keep following the correct cutter path.

If you were actually cutting an S in material and you had only left compensation on, the bottom of the S would follow the correct path but the top part would not.



 John

I thought I already explained it in one of my previous posts.

But in regards to following an S shape, you do NOT switch from left to right comp. If you are cutting out a letter S, you use the same comp, all the way around. You use Left or right depending on whether you want to climb cut or conventional cut.

Think of driving down a two lane road, and the center line is the toolpath. G42 is driving on the American side, G41 is driving on the British side. Changing the comp would cause you to cross the line. You never switch comp direction in the middle of a cut. If you drive along an S shaped road, you don't cross the center line when you switch from turning right to turning left, do you?

5927

General Mach Discussion / Re: how to fully fit mach 3 into a 17inch monitor

« on: August 09, 2008, 06:54:10 AM »

You can also close Mach3, right click in the middle of the desktop, and choose properties. Then click the settings tab, and change the resolution to 1024x768.

5928

General Mach Discussion / Re: Very basic question about tool diameter compensation

« on: August 08, 2008, 01:54:12 PM »

So I take it tool diameter compensation has to be done before Mach3?

The G-code needs the G41/G42/G40 in it, and must be coded correctly to allow for the lead in. But if you use G42 Dx, then all you'll ned to do is change the tool diameter in the tool table to make adjustments for tool size.

5929

General Mach Discussion / Re: Very basic question about tool diameter compensation

« on: August 07, 2008, 07:13:22 PM »

You don't need to set up the tool table to use comp, but you can if you like. There are two ways to use it. (Actually 3)

1) Call comp and specify the tool radius using the P word. For a 1/8" diameter bit, you'd use G41 P0.0625 or G42 P0.0625.

2) Call comp and specify the tool # in the tool table using the D word. This will use the radius of the tool in the table. To use comp with tool #3, use G41 D3 or G42 D3.

3) Basically the same as #2, but don't call any tool at all. Mach3 will use the diameter of the current tool (based on the diameter in the tool table). Just use G41 or G42.


To use comp properly, you need a lead in move where the comp is applied. Without comp, the center of the tool follows the g-code. When you call G41/G42, comp is applied during the move from the previous location to the one following the G41/G42. I like to use G41/G42 on it's own line, but you can combine it with the leadin move. Both of these will do the same thing:

G1 X0 Y0
G42 D1
G1 X1 Y1
G1 X2 Y1

is the same as

G1 X0 Y0
G1 G42 D1 X1 Y1
G1 X2 Y1


Once comp is applied, it remains in effect until you call G40. Depending on the move following the G40, comp can be either gradually or abruptly removed. You can use a leadout move, or you can raise the tool above the work and then remove the comp.

Left(G41) or right (G42) is pretty easy to figure out. Imagine walking along the toolpath in the cut direction. G42 will move the tool to the right side of the path, G41 will move it to the left side of the path. If you have a circular CCW toolpath, G42 will cut outside the toolpath, G41 will cut inside the toolpath. One thing that can be tricky is climb vs conventional cutting. Which method you're using will dictate whether you need G41/G42, as it determines the direction of the toolpath. The circular example above is using conventional cutting

Here's a little sample program that will show you how it works.

G40
M3
G0 Z0.1250
G0 X1.4629 Y1.2013 Z0.1250
G1 X1.4629 Y1.2013 Z0.0000 F25
G42P0.25
G1 X2.6956 Y2.0815 Z-0.2500 F50
G1 X8.2664 Y2.0815 Z-0.2500
G1 X8.2664 Y6.2744 Z-0.2500
G1 X3.4479 Y6.2744 Z-0.2500
G1 X3.4479 Y1.5214 Z-0.2500
G40
G1 X2.8556 Y0.9132 Z-0.2500
G0 X2.8556 Y0.9132 Z0.1250
G0 X0 Y0
M5
M30

5930

General Mach Discussion / Re: Very basic question about tool diameter compensation

« on: August 07, 2008, 01:35:15 PM »

What I must admit is that I have never been told what left and right mean - does that mean the tool is on the left or right - or the compensation is on the left or right.

Actually, those are both the same. Comp right would be to move the tool right.

There is another problem as well - where the cut finishes. Start the cut halfway along a straight edge and finish along the same straight edge, do not meet at a corner - because you do not know where the compensation is applied.

If you lift the tool before calling G40, you don't have to worry about it.

I think the OP needs a CAM package to do the offsets for him. V-Carve Pro and I believe SheetCAM will both do this. Does LazyCAM Pro do it as well?