...and it cuts/pockets 1/2" acrylic sheet too!
Attachment 1184

Sean,
That upper radius looks mighty smooth. Your machine seems to be Cutting great. :)

Heath.

No chatter, no "arc pulsing" either.
Almost perfect.....almost.
I still have to resurface the machine sacrificial spoilboard. My depth of cut is still off a smidgen in different parts of the table.
The picture is a little poor on resolution, rest assured, it's a really nice finish. I was able to go straight to flame polished edge without touching the plastic with sandpaper or burnishing tools. :)

Sean,
What do you use to do your flame polishing? Does that just gloss over the cut edge? Haven't done too much with acrylics myself. Where on earth did you pick up all these skills?

an alcohol flame or a hydrogen fired torch set (trick is NO carbon in the flame)....just wave it by the DA sanded plastic 220grit or better...and viola!....crystal clear. The finer the sand, the better the finish.

Skills....nope...just too many years doing "stuff". :)

I have never seen it that smooth, but then, I have never run with gearboxes. Have been picking up from posts like yours that the gearboxes make the world of a difference.

Gerald,
Didnt you mention at one time you were going to try the geared motors on one of your machines? That still in the works? Or am I remembering it wrong?

That is still in the works - waiting for a quite time when a machine is free for a few days.

Sean,

Could you post an example of a "hydrogen fired torch"?

Also, I can't remember... Do you have the 3.6 gearboxes or the 7.2?

Thx.

7.2 gearbox
the torch is your standard oxy/act brazing setup. Just substitute hydrogen for acytlene. Carefully wave invisible flame over plastic sanded to 400 grit or better.

Ok, I have an Oxy/ Actl setup. Do you get a hydrogen bottle at any welding supply? Never asked for that.

Next question...

With 7.2 gearboxes, what pinion and what is your max ipm jog speed?

Thx again.

Welding supply...ask for it. It's not something they usually get requests for from non-commercial users. You may have to assure them you using it for plastic polishing and not making a zeppelin.

7.2 gearboxs I am using a 20T pinion @25Khz = about 225 ipm jog
@ 45Khz = about 275
7.2 gearbox w/ 30T @ 25Khz = about 340ipm or about 6 inchs/second Doug is getting his table to achieve about 12" /second with 35T pinions.

Now, these speeds are well below what you can achieve mathematically. But, at these speeds, with my computer, etc....These "sound" about right.



I hope this helps.

Sean

Sean,

I'm actually jogging at 15.5 inches per second but I didn't build it to jog, I built it to cut. If I were doing it all over again, I would get a smaller pinion like you did or a 30T pinion.

Doug,
Would it be that hard to change the pinions around and see which one gives you the type of performance you want? Sorta like tuning the gearing on a car. Or is it a lot more work than it sounds?

It would be fairly simple and I may do it one day. The pinions are simple to change and then a couple of software changes. Right now, I'm spending all of my time at work.

Schematic for installation:
prox_layout.pdf

I received a message from Ed, but have also fielded a few queries from others on how the Proximity relays really work and how to wire them to the PMDX using only 1 input.

1 - refer to the pdf schematic link above. You can also see pictures of the installation in post 247 of my this thread.

Steps (and JR will keep me honest - I am nowhere near my machine right now to check things)

1 - wire according to schematic.
2 - set your mach 3 settings in the Ports and Pins box to input 15.(or your setting. For example. Map x - home to 15, map y - home to 15, map z - home to 15.
3 - I'll check my configs in the morning to see if I have it active hi or active low....I can't remember right now.


Mapping all the homes to the same pin number will allow mach 3 to cycle through the homing sequence and set the z, then y, then x.

In the Mach screen you push the long vertical bar (near the DRO readouts) to "refall" and it will run this sequence.

That is all. It works well and all the time.

thanks sean, I have mine working now.

There were some issues though. I am using pin 12. Doesn't matter you can use any of the unused pins on J5 as long as you enter that pin in the ports and pins. Remember also (i didn't at first) to assign A to home to the same pin #. After grinding gears for a second I remembered my slave motor.

I had to reverse the homing direction by changing to home neg for X,Y and A in the homing window of mach 3. Z doesn't have to change.

Active low boxes stay unchecked so they be active high.

Only issue I have left is the travel to home speed is slow all the time not just the last inch.

got the travel speed set now for 80% that is better

Ed

Good progress.

That travel will always be slow as when the machine is homing, it does not know where the the last inch is, it only knows to look for a limit switch somewhere in that direction. Its best to jog close to the limits and then "refall".

If I remember correctly, the big iron machines like Multicam will not allow you to jog until it is referenced, but Mach3 allows it.

Alan,
Your very correct. If you lost the home on my big multicam, you could not jog the machine except at "seek" speed. Which is the same slow speed it looks for the home switch. A real bummer if you lost home in the parked gantry 10 feet away from home. It took 10 minutes to rehome the machine!

Ed....great to hear you got it all worked out.

SEan

Sean,

Happy Birthday

Happy Birthday Sean! :D

Sooooo, How old are you now? :rolleyes:

Sean Happy Birthday, and may you get to be as old and wise as Gerald one day :D:D:D

Doug, be carefull with that 80% speed as it may try to home too fast and end up overshooting the limit. Homing, like setting Z at the surface of the job is best done sloooowly.

Here's a thought. Could a proximity switch be used to change the jog (feed) speed. If so, theoretically speaking, one could use two proximity switches set a few inches apart. When the first one is detected it will slow down the jog rate so you would not over run the second one when homing.

I'm only using Mach 3 on the test bench, not on my machine, so I'm not fully aware of the day to day sequence of events that you use when starting up your machines; however, on my machine, I manually jog the X and the Y axes to a point about 2 inches from the proximity sensors, and then run my homing routine. The manual jog, even from opposite ends of the machine, takes only a few seconds. I move the Z-axis to a point about 1/2-inch above the contact plate before running the Z-Zero routine.

Mike,
I do the same thing. It only takes a few seconds to get close, then run the routine. Works like a champ - every day.

Sean

I just checked, it takes 16 sec. to home 101" (full table length) on my machine.

Hi Sean,
After reading a few post on this proximity limits, I’m still very curious to see how you type of installation fits on the Y car.
I’ve seen your pics from your thread #247 and David’s new ones, but David uses Diell BIG 18mm in a different holder approach.
If not to much asking, could you post a few detail pics out of your Y car proxy installation ?
Thanks, Robert ;)

Robert,
I'll take a few tomorrow for you. Glad to be of assistance.
Sean

Robert,

I just closed up shop, but let me go back and take a couple of pic's of the Y car and prox. Be right back.