Y axis problems

[DocWheeler]

I am currently making a name-plate with a cardholder behind it similar to one I made a couple of years ago. There are three main mpcs plus one to carve out a region to inlay another color board so that the name shows up nicely.

The inlay pocket went without incident and I glued ¼” poplar (wishing I had some maple) into the purple heart board and reattached it to the sled. The next mpc recarved the board a smidge deeper, cut the letters, and formed the border. This attempt failed because the machine carved about 3/16” too high; toward the keypad. It only takes one pass to ruin the design and I don’t like the looks of a patch. So, I did it over again and it went without a hitch the second time. Here is a picture of a patch where the carve region for the inlay went too far.
This is the same behavior as what happened above and later on the bottom.


The cardholder is made of two boards in order to get it thick enough. The top of the cardholder has a slanted carved area with text and two pockets to hold business cards. The bottom board has two carve regions for added depth that match the cutouts in the top board plus I have text on the bottom of this bottom board. The top board carved, cut, and engraved without an issue. The bottom board was a bear.
Here are the three boards. I'm not doing the top veneer on this one.


The bottom board was a two-sided carve with text on the bottom and two carve regions on the top. The machine did a “verifying project” which I had never seen before and then asked me to “jog to front edge”, I have never seen that before and each of these mpcs were center-on-board. I have often had problems with two-sided carves but am always hopeful that they will work. Anyway, this glitch is not the topic of this post so I’ll just say that I broke that mpc into two parts and carved the text on the bottom. There was quite a bit of text, about an hour to carve it.

I turned the board over and started carving the two regions that form the bottom parts of the card pockets. This time, the bit started in the correct place, but went about 5/16” too far toward the top with the first pass and then returned the proper amount making proper sized carve in the wrong place. This is the same behavior that I have seen before and similar to what Version 1.133 did years ago.

The Y truck moves smoothly from side to side with the power off and the rails do not have a buildup on them; not perfect, but not bad at all.

An little off topic insight into my day: I have not carved much in a year or so, after using only my right arm to propel myself in a wheelchair for 43 years, my right shoulder wore out a year or so ago – bone-on-bone painful. So, last September I had my shoulder replaced and I now get about in an electric wheelchair. I got this power-chair five years ago but only used it occasionally; never even modified it to work in my van. I had wanted something strong and fast, so I got a Bounder. I now know why they call it a Bounder, it has two motors that when compared to normal power-chairs is like a Caterpillar engine compared to one found in an old Beetle. This sucker can do about 12 mph and can veer off at an angle instantly! It comes with a seatbelt even if you don’t drive from it! It is about 3” higher than my old chair so reaching the floor is wishful thinking, and moving about gracefully is a fading memory. I have broken wall tile in the bathroom, dented cabinets in the kitchen, and I am a continuous hazard to my two shorkies pups. So – taking the CW apart is not something to take lightly. Accidentally bump the joy-stick, drop a screw, back into the bench or drill press, oh well - you get the picture.

So, today I start taking my machine apart – the Y belt is tensioned correctly (and looks good for having 200 hours on it, I didn’t think I had that many hours). I took out the Y motor expecting to see damage somewhere, but it looks as good as new. I took off the dust cover to the optics in the back and find it clean and the disk firmly attached to the shaft.

Now what? I have this happen on two machines and a variety of projects.

[bergerud]

It sounds like you have checked virtually everything. The only thing I can think off would be the FFC ribbon. An intermittent connection interrupting encoder communication with the computer.

The "jog to front edge" (is it "Jog to front corner"?) is part of the flip-in-jig feature. You must have answered YES to the "Is the board in a jig?" You should have answered NO if you do not want to use that feature.

[DocWheeler]

Thanks for the reply Dan.
I was not aware of the new double-sided carve commands, I'll try to remember that.
I'll check the cable today. I think I'll turn the belt over so the other end gets more use.
Maybe I needed to have re-tensioned the belt a hundred hours ago!
It seems such a waste of energy to have to take the top off just to loosen and re-tighten a screw.
But, at this point, the belt seems to be the cause as far as I can tell.

[bergerud]

It seems such a waste of energy to have to take the top off just to loosen and re-tighten a screw.

I can get a stubby screwdriver in there to loosed the screw. But, maybe a hex head bolt would be better so one could use a wrench. Next time I have my machine apart, I think I will put in a stud with a nut. I worry about what happens when if those fine threads get stripped.

[dcalvin4]

Doc did you get your machine to run
denny

[DocWheeler]

Denny,

It has been a series of blunders so far, but thanks for asking.
Between getting the use of my arm back after shoulder surgery and dealing with some other
issues I find that I can not do the things that I did only two years ago. I can take it apart,
but getting it back together is beyond my current capability. My wife, who otherwise makes
my life possible, is reluctant to get into machine assembly and I am relying on a good friend.
After I took it apart and had him help with the Z-encoder cover to get out dust we assembled it.
When I later used it, it did the Y stuff so I disassembled it and had Dan come back again to put
it together - I did not test it. When I went to use it, I got all kinds of errors, the ribbon cable
had gotten pulled out of the contacts. I found that out when I took it apart for the third time.
While it was topless I went ahead and took out the Z-motor and found slop in the gears. So-
now I'm awaiting Dan's return Tuesday.

It should be in pretty good shape next week after all of the attention it has had.

[DocWheeler]

I want to have one more attempt to see if anyone can help with this.

The problem I've had with two machines has been with the "Y positioning.
I'll not include the first time which led me to purchase my second machine
and just describe in more detail what this machine has done.

The first board was ruined when the bit started its first pass about a half inch high.
The second pass has another half in too high before I got it shut off. I cleaned and
examined everything - even replaced the Y belt.

The next attempt to carve resulted in th starting about a half inch too high. Since it
was a test, I let it carve since I wanted to test the X result as well. There was no
further Y displacement, it carved both 1" X 2.25" regions with the same offset error
that the first pass created.

The photo in my first post was taken several years ago where the same thing
happened and I didn't notice until it had made several passes. I filled it with sawdust
and glue after restarting the carve and it started in the correct place. The final
carve that created the letters started in the right place as has most carvings
since that time.

What would be the cause of losing the Y position on the very first carve and
then, almost always, carve at the same Y positions? What is so special about
the first Y movement? What Hardware component could cause it?
What would you do?