Pattern “automagically” offsets on Y axis during carve session

[Z-clip]

Pattern “automagically” offsets on Y axis during carve session

I’m having an ongoing issue with the machine offsetting the pattern it’s carving. I’ve bounced this problem off Tech Support and though I provided pictures and worded it best I could, their response held nothing to do with the actual problem and was geared towards dealing with issues with the Z axis, which is working just fine.(big "ups" to Phillipe & Alex, phone support. They were actually helpful as they could be) I’m turning to the community now in hopes that someone else has encountered and successfully dealt with this problem. Here are the pertinent details:

When carving patterns in cherry, my end product stock (never happens in the MDF test boards, ALWAYS in the cherry, naturally), the carving motor boggs down and then spins back up. When I get over to look at it, the machine has offset the pattern on the Y axis. It has done this in several boards, and always offsets towards the “Near” side of the machine. (ref: CarveWright_manual_A-B_SN.pdf / Page 17 / Figure 13: Directional Conventions) When I stop the project I usually get a Y-axis stall error message at the key pad (Duh, ya think?) though this last episode it paused itself & told me to clean the rails which seemed clean, but ok, sure, THEN gave me the Y-axis stall message.

Now, PREVIOUS to this I was having problems with the cover sensor switch & head termination board, both of which I replaced. While I had the cover off I checked the Truck action on both Y and Z axie and fount the Y to action to be somewhat “crunchy” and halting in it's travel. I cleaned and lightly lubed the rail with some 3in1, and cleaned the rollers best I could. The action was about the same, so I adjusted the alignment, and that solved the problem, or at least from there I got smooth, solid tracking up and down the length of the Y-rail. Also, while in there, I cleaned & repacked the Y gearbox w/ White Li Grease (cream, not spray) and resealed the gear cover with LHR suggested silicon sealant.

I got it all back together, and went to cut a test board, the truck would not track all the way to the “Far” end during homing, I decided since it had the Y-axis offset problem, the machine was probably out of calibration on that axis. Since the truck stopped close to the “Far” end of the rail and tride to home at that position, I deduced that was where it though the “Knife Lever” (Used in bit homing though I can’t find the part listed, so Knife Lever is what I’m calling it) was supposed to be. To correct this I slipped the Y motor, moved the truck by hand to the “far” end of the rail, and reinstalled the Y motor and readjusted the belt tension. I also took the opportunity to lubricate the flex shaft as per maintenance instructions. (Ref: CarveWright_service_lubricate_flexshaft_core), and got it properly seated & reinstalled

Test cut in MDF worked great, The Cherry, of course didn’t. The rubber cover on the Flex Shaft melted off at the apex of its curve. After getting a replacement Shaft delivered & installed, I rand a short test, worked great. Loaded my last cherry board (design adjusted to allow for missing pieces from previous botched sessions) and went to carve. Measured and tracked everything great, all 116.75” of length. (Supported with 10’ conveyer rollers at both ends). I purposefully had an extra 20” minimum calculated into the length incase the machine failed again, (Fool me once shame on you, fool me…six times, shame on me) which it did.

On the personal side of this, I really love the concept of the machine. It pains me that it was “not ready for primetime” when it came out, but that’s usually the price for new tech. This is the first paying gig that I’ve run through the machine, and I’m knida paying a hefty “tuition” at this point, this could very well be the last straw w/ the Carvewright.

Absolutely ANYONE who has had similar woes, I would greatly appreciate your input, even if you didn’t get your problem solved as it might be helpful in figuring out a workaround (barring a straight up fix), and if you have a fix I definitely want to hear from you. Here is hoping it’s a serviceable issue, as for now, my “happy ***” is tapped out, so no more parts can be ordered.

Also, if there are any users in the Austin, Texas area, and would be willing to barter to run this pattern, I want to hear from you.

Thanks folks for your time and attention. Happy holidays.
-Z-

[dbfletcher]

You didnt say what setting you were carving at. If you are not using Optimal, I would recompile and try again. Optimal takes much smaller x-increments so the load on the Y axis when carving is less. It really sounds like the machine is jumping a tooth or two on the y belt which then causes your offset.

[bergerud]

I have had the y belt slip because of a carving transition from shallow to a deep plunge. If the belt is not tight or the bit new, the belt slips and the carve shifts and then it stalls. Check the belt tension and the bit condition. (Only the last 1/4" of the bit seems to get dull.) You should also post a picture.

[Z-clip]

Thanks folks,

Ok, my quality is set to Normal, I'll change that to Optimal as you suggest, though the 22hour carve estimate makes me cringe. (still, I need to get through this). I was looking at the bit after I posted the first message, it probably IS in need of replacing, but I just can't do that ATM, so hopefully the quality change will help. I'm certain I have good tention on the belt, but the offset made me think of slipping teeth as well, I didn't think about that being a bit issue so much as a problem with the rail & wheels. Here is a comparative picture of the first time this happened:
49651

The top piece carved properly, and has already been freed from the plank, the bottom piece shows the Y-axis offset (offset appears vertically in picture).

Just incase it's useful, here is the project file for the last plank:49652 (I hope) The Zero carve region is in place to stop the Carvewright from putting an undesired corner at the "top" of the carving at either end.

[bergerud]

Yep, its the plunge. You will notice that the shift happens whenever the bit has to plunge down to a new level. I regard this as a programming error. The machine should slow down the carve when level changes abruptly from high to low. I make sure I always go from low to high. You cannot do that with your pattern. Draft would help if you use it. (Not he draft carving rate when you upload but draft under the carving menu in Designer.) It slows the transition from high to low.

[TerryT]

The cut motor is supposed to change speeds during a project depending on wood and conditions, pattern, text, etc.

If you have between 200 and 500 hours on your machine the shaft bearings in the Y transmission may be worn causing the shaft to tilt towards the tensioning screw and bind up. You can replace these bearings if the shaft has not worn. Search for Al's pictures on the Y motor bearings. MDF cuts pretty easy. The extra drag of cutting Cherry may be pulling the big "Y" gear to the side and hitting the housing.

[mtylerfl]

Z-clip,

Several excellent suggestions for solutions and pretty much all related in one way or another. Changing from the "Normal" setting to "Optimal" should do the trick to eliminate the shifting when plunging and carving.

The "Normal" speed/feed rates are too fast for Cherry and other hardwoods. I only use "Best" or "Optimal" on all my projects (even softwoods) too keep quality up and stress on the machine down. There should probably be a recommendation in the CW documentation somewhere to use "Draft" or "Normal" only on softer materials and when you don't care all that much about the quality of the outcome.:)

Question for you...Where did you get the 10' conveyer roller supports (are they 'accordian style' to fold up smaller for storage)? I have a couple projects in mind (bookcase, bedframe and headboard) that those could come in very handy for supporting long boards more easily!

[Z-clip]

Thanks again for the help folks, Tomorrow I'll give it another go, time permitting.



The "Normal" speed/feed rates are too fast for Cherry and other hardwoods

When I first started working with the software, I thought that "Pine" or "Oak" under Board Settings was necessary for secifying hard or soft wood, not just to make it look pretty in the designer. I was also puzzled as to why there was only Pine and Oak, and not other choices, That would be a good place to specify a "hardness" variable for the machine to govern cutter/feed rates,,, hope LHR is watching :)
____________


If you have between 200 and 500 hours on your machine the shaft bearings in the Y transmission may be worn causing the shaft to tilt towards the tensioning screw and bind up.
I went and checked the Odo reads 76H 58m cut time, though it occours to me I started to learn the joy of mechanical problems somewhere between 16 & 30 hrs. The machine is a B series, I figure if I'm still using the carvewright when they hit L series, I'll reinvest.
____________


Draft would help if you use it. (Not he draft carving rate when you upload but draft under the carving menu in Designer.) It slows the transition from high to low.
I'll give that a looksee. Thanks.
___________

Plunge, plunge, plunge,, ya know I bet your right. You know how the machine has a sort of "rhythm" as it's going through the carving process (as opposed to a "cutting" process) It seems the bogging sound occours at one end or the other of a swipe, or so it would seem. Never happens when you're watching. But that's where the deepest plunges occour not counting the ends which are consistant depth across the Y travel, so I'm thinking less likely to get stressed.

Thanks once again folks for your time & thoughts. I'll post an update sometime Sunday, though it may have to wait till the next bout of rains pass (Projected rains Sunday thru Thrus, and I won't run long stock thru the machine during rain days since it's under the cantilever & not in the shop.)

Gratefully
-Z-

Oh yeah..


Question for you...Where did you get the 10' conveyer supports?

Amazing luck, to be honest. Was looking for a way to support longer stock so I could do things like carved bed rails & what not. Was just about ready to make a couple conveyor rollers out of oak closet rod & old skateboard berrings, and these things fortuitiously popped up on my local Freecycle list (Awesome resource BTW). The guy makes custom carpets & rugs, and got them from a local warehouse/shipping supply. I had to go halfway cross town & he helped me load them, So smashing deal all around. They pull double duty to support long stock in & out of my planer as well. I had to make support brackets outta bed rails & mount them to the side of my shop under an overhang to keep em outta direct weather, but they totally rock. So if you don't want to cross drill & cup hole a buncha closet rods (or find berrings that fit in 2" PVC pipe) I'd suggest checking for used shipping supply houses, and if you find some that aren't hidiously expensive, make sure to bring a strong friend and a long bed or trailer,, and maybe some doan's pills for later.

[liquidguitars]

There should probably be a recommendation in the CW documentation somewhere to use "Draft" or "Normal" only on softer materials and when you don't care all that much about the quality of the outcome.:smile:



As one that owns a high speed Delta shaper faster feed rates are not necessarily a bad thing when milling hard woods. Designer's Draft mode can be used for hard woods like maple without issues as long as the tooling is sharp and your y pack are not worn out.

I would go with the Y pack as the issue 2, try this, press down on the y gear with your finger if it's soft or moves alot i would replace it... also check the belts.

[liquidguitars]

Yep, its the plunge. You will notice that the shift happens whenever the bit has to plunge down to a new level. I regard this as a programming error.

I do not think so, this normally is a combination of a dull bit and a bad y pack, normally...

[mtylerfl]

As one that owns a high speed Delta shaper faster feed rates are not necessarily a bad thing when milling hard woods. Designer's Draft mode can be used for hard woods like maple without issues as long as the tooling is sharp and your y pack are not worn out...

Interesting. I've not used Draft mode so I can't say how it performs in hardwoods. Tried Normal several times on Pine and once on Oak and once on Maple...won't do that again...sounded like it was pretty "hard" on the machine (made me nervous, but no mishaps occurred). Mainly the quality of carve suffered so much, that I stick with Best or Optimal on everything now.

One thing I have found on my brand-x machine (ShopBot Buddy PRS ALPHA) is that my carves and cuts on hardwoods such as Maple, Beech, Oak, Alder generally yield the best quality (clean cuts/carves and no chipout) if the spindle is running fairly high RPM's for carving (15 to 18K) but slower for pocketing and cutting (10 to 12K). Also get great results using slower feed and plunge rates (around 0.5" per second for intricate V-carving to about 2" to 3" per second for detailed cutting/carving). Of course, a lot depends on the chunk of wood itself - I can go faster or slower on all settings depending. I've done such a huge variety of projects now on both the CarveWrights and the ShopBot, that I think I'm beginning to be able to tell what rpm's/feed/speed rates will work well just by looking and handling the wood!:mad:

[liquidguitars]

Cool MT... BTW Draft mode works killer with the 3/16" ball nose on maple and ebony as long as the designs can handle the bigger 3/16" end... talk about getting things finished up...

[mtylerfl]

Cool MT... BTW Draft mode works killer with the 3/16" ball nose on maple and ebony as long as the designs can handle the bigger 3/16" end... talk about getting things finished up...

Ahh, yes. I have not tried the 3/16" BN on Draft or Normal...I can see where that might indeed be workable alright. I need to try that myself!

[Scott31]

Just read the y axis issue as I am having this problem. Going to try changing to best carving. I tightened the y belt but can't see how tight is should be... hate to have it over tight. Does anyone know where I can find specs ? Or proper way to know how tight it should be. Thanks in advance for help.

[mtylerfl]

Just read the y axis issue as I am having this problem. Going to try changing to best carving. I tightened the y belt but can't see how tight is should be... hate to have it over tight. Does anyone know where I can find specs ? Or proper way to know how tight it should be. Thanks in advance for help.

Hi Scott,

The Y-tension adjustment is automatic...easy to do. Just loosen the Y-tension plate screw so the plate can move freely along the slot, then re-tighten it (you'll need a "stubby" #2 philips screwdriver). That's it! There is a spring that adjusts the Y-belt to the proper tension automatically.

[dcalvin4]

had problem with mine and changed the y bearings [1 was bad] then discovered the shaft coming thru the mounting frame that holds the small plastic gear for the belt was rubbing on the frame making it hard to move I readjusted the whole motor housing '' up'' higher so it wouldnt rub an now it works .
So i would suggest moving the y by hand back and forth and look to see if it rubs
Hope this helps
denny

[DocWheeler]

There have been good responses to the initial post.

I have had this problem twice and resolved them both times, but I think my second "fix" might be temporary.
I enlarged your picture and noted that the first-error, the first carve that went too far, is about the length of a belt-cog.
To me, this would indicate the belt jumped a cog - and Michael's last post should fix that unless you have a lot of hours,
then Al would have answered the main problem with his first post if there is excessive wear (more drag and less belt tension).

Getting the belt to jump a cog (slip one cog) could indicate that there is still too much energy to move the Y truck.

The second problem/fix that I mentioned was where the very first pass in the Y direction was wrong, still don't know why.
My work-around was to have it do a minor cut prior to getting to the first starting piont that I wanted.
This happened several times when doing a simple 1/4" region with no pattern involved.

[Z-clip]

Heh, well, I did finally make it through this project. Sadly the carvewright became so problematic that I had to take the job to another shop with a larger CNC machine. I think the problem was the cog slipping, and I believe that was brought on by pushing the carving bit through too much stock.

I spoke at length with the shop owner (She was using a Shop Bot, I believe) and gleaned a most useful pearl of wisdom...which in retrospect, now seems intuitively obvious, 'Use the cutting bit to remove large areas first, then use the carving bit to go back and work the details.'

So before I run a DXF/STL import, I must make paths & routed regions to lighten the load for the carve session. I honestly don't know if I can do this with the Carvewright, I think it would be best to combine the paths and the carve into one project, but I don't know how to tell the machine to route first, then carve and I've had no time to adjust the tracking on the machine (which has gotten worse to the point where it lurches just moving the Z-truck along the Y rail with no load).

I donno if I will repair and keep it for small detail pieces like the medallions (pictures below) or repair and sell it. The shop owner with the larger CNC machine offers classes to the public (assuming they have woodworking skills/knowledge/experience) for using the software and running projects on the CNC so that "certified" folks can reserve time on the machine and pay a reduced rate to run their own projects (feeling obligated to mention here that her regular rate for the CNC is already extremely reasonable when compared to other shops in town). I still feel kinda torn between loving the Carvewright concept, and being sorely displeased with it's performance. Couple that with things like not including an importer with the design software that lets you bring in DXF/STL files (which ALL other design software packages do...that's right, I said 'ALL' ) and shipping the unit stock with the sucky sandpaper belt, charging extra for the good traction belt, (I'm waiting to see if they offer a brass gear upgrade package for $500 *snicker*) it's difficult for me to stay jazzed about the equipment.

Anyways, I certainly appreciate the helpful and insightful input from everyone responding. Here are a few shots of the finished project. Cherry valances with Wenge and copper nail accents in a Chinese motif. Thanks to all -Z-

577475774957750

[Nick68]

Had the same issue long ago, jumping a tooth along the y axis or just plain boging down until I got a stall error. Check the Idle Pulley Assembly for gummy or worn brass. Its a 5$ part...While your at it check this same part located at the base of the Z truck.

[Scott31]

ok.. thanks..

[bergerud]

had problem with mine and changed the y bearings [1 was bad] then discovered the shaft coming thru the mounting frame that holds the small plastic gear for the belt was rubbing on the frame making it hard to move I readjusted the whole motor housing '' up'' higher so it wouldnt rub an now it works .
So i would suggest moving the y by hand back and forth and look to see if it rubs
Hope this helps
denny

If you mean that the y motor drive sprocket was rubbing on the machine casing, your bearings behind the big plastic gear may be shot. This usually happens around the 500 hour mark. If left too long, the shaft will get damaged. If caught early, one can replace the bearings.

[badbert]

Heh, well, I did finally make it through this project. Sadly the carvewright became so problematic that I had to take the job to another shop with a larger CNC machine. I think the problem was the cog slipping, and I believe that was brought on by pushing the carving bit through too much stock.

I spoke at length with the shop owner (She was using a Shop Bot, I believe) and gleaned a most useful pearl of wisdom...which in retrospect, now seems intuitively obvious, 'Use the cutting bit to remove large areas first, then use the carving bit to go back and work the details.'

So before I run a DXF/STL import, I must make paths & routed regions to lighten the load for the carve session. I honestly don't know if I can do this with the Carvewright, I think it would be best to combine the paths and the carve into one project, but I don't know how to tell the machine to route first, then carve and I've had no time to adjust the tracking on the machine (which has gotten worse to the point where it lurches just moving the Z-truck along the Y rail with no load).

I donno if I will repair and keep it for small detail pieces like the medallions (pictures below) or repair and sell it. The shop owner with the larger CNC machine offers classes to the public (assuming they have woodworking skills/knowledge/experience) for using the software and running projects on the CNC so that "certified" folks can reserve time on the machine and pay a reduced rate to run their own projects (feeling obligated to mention here that her regular rate for the CNC is already extremely reasonable when compared to other shops in town). I still feel kinda torn between loving the Carvewright concept, and being sorely displeased with it's performance. Couple that with things like not including an importer with the design software that lets you bring in DXF/STL files (which ALL other design software packages do...that's right, I said 'ALL' ) and shipping the unit stock with the sucky sandpaper belt, charging extra for the good traction belt, (I'm waiting to see if they offer a brass gear upgrade package for $500 *snicker*) it's difficult for me to stay jazzed about the equipment.

Anyways, I certainly appreciate the helpful and insightful input from everyone responding. Here are a few shots of the finished project. Cherry valances with Wenge and copper nail accents in a Chinese motif. Thanks to all -Z-

577475774957750

Regardless of who carved them, they came out beautiful. You seem like a talented person, the Carvewright could only compliment your work.
With that said... there is only one reason that the carvewright can't carve that project. Not properly diagnosing the problem. I have carved many project larger and more complex than this project. I strongly urge you to disassemble the Y drive. And to re-inspect the gears and the bearings for the Trans gear. You also need to check the Y-truck bearings. The carvewright doesn't just slip a cog unless something is not right. As a 30 year retired technician, there is one thing most people get tripped up by. A new part does not always mean a good part. Low hours on the machine does not mean it can't be broken or defective. If you post the pattern maybe one of us can carve it to prove this theory.

[Digitalwoodshop]

I agree with the above post... I would remove the Y Motor and strip it down and look for wiggle in the big plastic gear... As long as the motor is out, check for a frozen Y Bearing... I found one frozen in the Y and one in the Z when I did my 250 hour maintenance.

I recommend you look up that long post and do a 250 hour disassembly, clean, repair, and lube...

AL