Messages

1

General Mach Discussion / Re: mach 4 learning the machine drive ratios

« on: December 19, 2020, 03:26:31 PM »

That makes perfect sense. The  ballscrews are the same. Also, as I understand, servo hold is determined by position. How does the "brake" function work on your braked servo?
Is there a possibility for a conflict between programmed stop, and applied brake stopping the servo short of its programmed satisfied position? In other words, could the brake apply causing the servo to continuously keep attempting to reach perfect position?
Thanks again for your generosity, and understanding dealing with someone with entry level , if that, skills. Chris

2

General Mach Discussion / Re: mach 4 learning the machine drive ratios

« on: December 18, 2020, 02:54:58 PM »

Your counsel is super immensely appreciated. I think that long after I have forgotten how much they cost, I will be living with the results. Right once beats twice cheap every time. Therefore, I will be focusing on servos. Its tempting to go with steppers, but I want to continue to like/love my machine instead of the alternative. Success breads success.
 I already feel like you have steered me around big trouble. I think I will still do a 2:1 drive, and the 750w servos. I think I will be very happy with those results.
Again, much appreciated, and thanks, Chris.
BTW, what profile and size are your servo drive shafts?

3

General Mach Discussion / Re: mach 4 learning the machine drive ratios

« on: December 17, 2020, 09:32:28 PM »

I was referring to the quill as the z axis. I am thinking that the knee will be "set" for a given operation. Once set, than the tool heights, fixturing and work can be programmed. My understanding of the machine is that all the dynamic functions of all the motors will be
x/y and the quill I'm referring to as z. I will focus on getting this machine functioning as well as I can get it with my limited skill set. I don't want my personal skill limits to compromise the build, but its not going into production either. Our discussions have already corrected a huge amount of mistakes not yet made. If I can get this machine to run well, maybe it will enable me to run well. That's the goal. I'm looking for the "goldilocks" outcome for my little situation.  That said, I would like to be conservative, but not cheap. I seem to want to overbuild everything, but I have in the past underbuilt, and have reaped the consequences.
Thanks again, Chris

4

General Mach Discussion / Re: mach 4 learning the machine drive ratios

« on: December 17, 2020, 11:16:29 AM »

BTW. There is absolutely no hurry. I'm way beyond that. . Being in a hurry is a young mans sport. Right once is always faster than twice fast.

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General Mach Discussion / Re: mach 4 learning the machine drive ratios

« on: December 17, 2020, 11:11:33 AM »

Craig, I'm blown away by your expertise. The z axis belt and pulleys are trapezoid, the spindle is ball screw. The spindle has an air operated variable pulley system for speed control, and an air operated transmission brake for the spindle. This is a pretty beefy machine. It weighs in at just under 3200 lbs. The z axis ball screw has a barely  perceptible "load", or drag when moved with hand motion on the belt. Its really free with no backlash. I think that's why Bridgeport used trapezoid belts and pulleys for the z axis.

I think that these drive systems on the x/y were 1:2. The nearest drive pulleys I can find in HTD 8mm is an 18 tooth. available in aluminum, or plastic.  I can go larger. I think this might be an opportunity to maximize motor capacity, or resolution. What do you think. I cant begin to express my gratitude for your assistance. This is a really fine machine. Thanks again. Chris.

6

General Mach Discussion / Re: mach 4 learning the machine drive ratios

« on: December 15, 2020, 10:42:17 AM »

also, is there an opportunity to correct any undesirable calculations with a drive gear change?

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General Mach Discussion / Re: mach 4 learning the machine drive ratios

« on: December 14, 2020, 04:59:22 PM »

many thanks

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General Mach Discussion / Re: mach 4 learning the machine drive ratios

« on: December 14, 2020, 10:45:21 AM »

btw, both driven pulleys are HTD 40 tooth, 8mm, steel
the z axis is 26 driven steel trapezoid with a 5 inch travel
I may have the same ball screws that you do.

9

General Mach Discussion / Re: mach 4 learning the machine drive ratios

« on: December 14, 2020, 10:31:31 AM »

perfect.
The major on the ball screws are 32mm
Pitch is approx 6mm as measured with a pair of vary nears
length of x axis is 686mm
length of y axis is 737
These are measured roughly with the machine assembled.
I measured rotating torque with a snap on torque meter.
7.5 inlbs break torque
5 in lbs rotating.
resolution is poor at best.
no motor or drive pulleys
Thanks again. Chris

10

General Mach Discussion / Re: mach 4 learning the machine drive ratios

« on: December 13, 2020, 07:50:34 PM »

correction, coloradochris2000@gmail.com