Retrofitting a 1986 Maho MH400E
snoozer77 wrote: Just an opinion on physical run, pause and stop buttons. I use machines with both types of controls. One large vertical borer with retrofitted touch screen only, and another reftrofitted mill with normal screen and physical buttons. I believe having physical buttons is safer (on the machines i use) as you can always have your finger on the physical button, while you watch the machine, waiting for something unexpected to happen.........
In the end, it comes down to personal preference. Whatever your comfortable with.
I agree about a physical button. With the touch screen, you have no tactile feedback if your stop finger moved while looking away to the work or spindle. That is what is cool about gmoccapy. When you need your physical run/pause/stop button, it is there. When you are not in mode where you are running a program, it is freed up for a different purpose.
Program run mode...
There is also some ".A" axis lust and a very brief bit on his coolant system. Wish Mr Roger M would video more on those machines --- Hint Hint Wish Wish
Mark looking at the remains of the slotter cutting bit -- I am wondering if that was just a excuse to justify having a tool & cutter grinder ?
I picked up the Clarkson from a friend a couple of years ago (he upgraded to a Tos, which is a dream machine, especially now with the Haller sprial grinding attachment he scored at auction - there is a picture in the madmodder thread). Having a T&C grider was a bit of a luxury, until I started abusing end mills with the MAHO.
I finished off the anvil job using the face mill. There is a large hard spot in the middle, and I had to slow down to 80rpm, 80mm/min at 0.2 Ap to prevent it chattering.
J Green wrote: Wish Mr Roger M would video more on those machines
It's a pity his f1-2000.co.uk web site has gone down, it had some amazing pics of the tiny parts he is making for his 1/4 scale Ferarri engine. Like this one: goo.gl/images/FknhTL
Unfortunately, this again indicated that the Y-axis creeps. I notice that the cutter was only touching at the front (-Y). After centering it better, I reoccurred.
I ran a test and such enough, there are drop outs on the B channel of the Y encoder.
It was cold in the basement so I took a break. Since I now have a single channel 602EXE on Z, and it is wired with the differential signals, I will use that to test whether it is an EMI noise issue.
Could you recruit some old analog electronic hobbiest person/codger that has analog test gear , like a real analog scope an analog variable power supply. -- be sure to quiz them about making shop/house visits.
The cold Maho -- I have used a rigged up tent made from rigid electrical conduit frame with U clamps and plastic film type cover that used a electric heater . Takes a while to warm up the metal such that my tongue doesn't stick to the Maho..
Was useful for painting also.
be very careful as you might fall into that need of spindle indexing trap
Hope you find the scale issue very soon
Bob who is --- cold old analog
Hanno, one of the German guys who is also converting a MAHO also identified that cheap chinese 5VDC PSU as a potential cause. He pointed out from the datasheet that the isolation at 100MOhm/500VDC is not very good.
He also suggested a metal EMI shield over the 7i77, like I put over the EXE.
Here is a my plan for trouble shooting:
1/ Switch the Y and Z axis encoders exe's. This is easy as I just switch encoder and 7i77 connectors. Z has a stand alone 602 EXE, which only takes 5V power. The three channel board mounted EXE on X and Y also has 12V supply which I pulled from the ITX MoBo PSE. Since the 602EXE also has the differential signals output from the EXE--> 7i77, I am hoping to isolate with this step whether the problem is in the EXE or the Encoder.
2/ Make up a battery PSU per your suggestion. I bought an assortment of resisters at some stage, so it will be easy enough to bodge up a battery pack, tuned for 5V output. Thanks for that suggestion. If that works, would replacing the cheap 5VDC PSU with a name brand rail mount PSU be expected to also work, or do I need to do more to solve a problem like this?
3/ According to all the EXE datasheets I have been able to find, the differential signals should be available on the three axis board. They were just not brought out to the Phillips on the output cables. If the interference is is being picked up on those last cables, I could try replacing them and and bringing out the differential signals on twisted pairs.
I once read a post about changing the size of the letters/keys on the Matchbox virtual keyboard, but can't find it again. If anyone could point me in the right direction I would appreciate it.