Messages

21

General Mach Discussion / Re: cutting a spiral

« on: September 18, 2018, 01:02:29 PM »

CamBam does spirals too. I cut flange faces to mate to round tanks. I project the spiral onto a surface with the tank radius and spiral inwards from the outside edge. Very efficient tool path.

22

General Mach Discussion / Re: Z losing zero position in rapid move up

« on: September 13, 2018, 09:48:30 AM »

Unlikely to be backlash especially on the Z as gravity mostly keeps the nut down against the screw. Likely to be loosing steps because you say it doesn’t occur when jogging which is done at the maximum torque part of the motor speed curve. Rapids take the motor into the part of the curve where torque falls way off.

For best performance I would try reducing maximum motor speed not acceleration first. Reducing acceleration will make cutting times go way up when lots of short moves are needed. Reducing max speed only slows long rapid moves

23

Mach3 and G-Rex / Re: How to run mach3 for multiple cycles?

« on: September 07, 2018, 01:52:48 PM »

If you don’t have Cam then you can program the part incrementally and put that code in a subroutine. Program absolute start position and call the sub, new position call the sub, until you done. I’ve done lots of that 20 years ago. CAM is too easy and cheap to waste my time that way anymore.

24

Show"N"Tell ( What you have made with your CNC machine.) / Re: Milldred gets some

« on: September 03, 2018, 01:20:36 PM »

The thing slowing you down is acceleration. With a trapezoidal move profile you simply don't get to speed on a short move. Depending on where you are currently a higher voltage power supply, if the drives can handle it may help a lot.  The next step would be bigger motors and or drives.  If you go new motors get low inductance ones as that makes a big difference too.

My machine moves at 7600 mm/min rapids with 68vdc power supply and large nema 34 steppers. It gets up to speed scary fast!  Big CNC machines can do huge accelerations which is what actually reduces the cutting time.

25

General Mach Discussion / Re: Seeking some help on "drifting" X axis

« on: August 31, 2018, 02:08:22 PM »

Patience,
I think people here are losing that because all that was asked for was the g-code file that went with the pen output you showed first. Instead you are doing everything but what was asked and you are getting no closer to the answer.

26

General Mach Discussion / Re: IF you could add new Gcode functions to Mach3 what would you want?

« on: August 30, 2018, 01:16:43 PM »

Most of the mill requests are for features useful to people programming by hand. The single biggest change in CNC is CAM. I have extensive hand programming experience. I use a CAM program almost exclusively now. The big bed mill we purchased for a tiny fraction of new was because the company that owned it could not justify the programming time for small quantities. We blow out single parts all the time.

Every CNC machine has idiosynchrosies like Mach 3. That is why CAM programs have post processors. You edit the post for your machine and all those issues go away. CamBam and others, the best $150 upgrade you can make on your machine.

The beauty of Mach 3/4 is that the control is a PC and you can run the CAM program right alongside.  Mere seconds to edit the CAM file and reload it into Mach3/4. Just broke your last 3/8” tool and only have a 1/4” for that pocket? Change it in CAM repost it, load the code and tool and finish the job.

27

General Mach Discussion / Re: Seeking some help on "drifting" X axis

« on: August 29, 2018, 09:09:19 PM »

Still looks like a G-code problem to me. Actual axis drift would have resulted in ovals not circles.  It sounds like your program might have generated in incremental code rather than absolute and all the increments plus and minus don’t add up to zero. Incremental is common for nesting because you can put the motion code in a subroutine and move to a new starting location for each instance.

28

General Mach Discussion / A little noise

« on: August 29, 2018, 08:10:07 AM »

I’ve been building control panels for nearly 50 years, so I am well aware of noise issues and very seldom have a problem. Proper grounding, shielded cables, control wires on opposite side of cabinet from power wires, flyback diodes, etc.  Recently I was building a solenoid pump driver. I needed one flyback diode on the coil and with the demise of Radio Shack could not get one quickly. So I took the one on the spindle relay on my Mach 3 mill.

A few weeks went by and I set up job and noticed a large thump noise as I turned the spindle on and off. Then I saw that all 4 axis were jumping a full step every time the spindle turned off!  I’m thinking “Nah, couldn’t be that missing diode.”  The replacement had come in and sure enough that solved the problem!

I’d bet half the troubles we see here are due to simple stuff like this.

29

General Mach Discussion / Re: Seeking some help on "drifting" X axis

« on: August 28, 2018, 06:50:37 PM »

Looking at your photo it can’t be a step loss problem because the circle centers are moving closer together and yet they are still round! Look at your G-code because it has to be the problem.

30

General Mach Discussion / Re: Noob here

« on: August 27, 2018, 01:55:31 PM »

The machine you point to is USB. No parallel port required. Fusion generates G-code and any program with CAM in the name should also, that’s the purpose of cam. A cam program is a good way to learn how to read G-code. Generate some code, load it to your machine and put Mach 3 in single step mode. Read each line and look up what the machine should do. Then press start and the line will execute and show you what it does. You don’t really need to write G-code by hand any more but reading it is still inportant in avoiding problems. CNCs are completely stupid. Tell it to crash into your part, clamp, end stops, and it WILL do or die!