Coupler damaged

[aluomala]

I have had my machine (AR4+Pro) for about 2 weeks now,  and have been running it pretty hard: lots of 3D carving, and run times of 4-5 hrs on average (some roughing passes of 2-3 hours, some finishing passes of 12+ hrs). This is my 3rd CNC machine (the first was a DIY ShapeOko2 kit, then a NWA PirahnaFX, and now this machine) so I was ready to hit the ground sprinting.

I had read about couplers (specifically the z-axis) becoming damaged, so while I was waiting for my machine to get delivered (the 2-3 weeks for expected delivery turned into 9 weeks...) I ordered some new couplers (I got them via Amazon.ca at this link) [They are known as 8mm x 6.35 mm CNC Flexible Plum Coupling Shaft Coupler, in case that link isn't helpful]

The other day, I noticed a piece of red plastic on my spoilboard (while a job was running) and couldn't figure out where it came from (I think most of you can see where this is headed....), so I ignored it.... Until today, when I saw another similar piece on my spoilboard (after I make sure everything is running smoothly, I will go into the house (shop is in my attached garage) and then check on the machine periodically). Anyway, I clued in that something bad was happening and I paused the run, and took off the cover for the z-axis to investigate. Sure enough, the plastic pieces were from the coupler. Oddly, I hadn't had any issues with my z-axis cuts. I decided to do a breakpoint and replace the coupler. In less than an hour I was back in action (I HAVE to invest in very long allen keys (hex keys), since the part that took the longest was disassembling the z-axis motor from the mount, and standard length hex/allen keys are too short).

Anyway, I decided to post pictures of the coupler "fragments" so people know what it looks like when they start falling out of the z-axis mount onto their spoilboard (I still feel pretty dumb for not recogzining them for what they are, considering I sometimes get mesmerized by the x-axis coupler spinning around when I have nothing better to do...

On another note, why doesn't Axiom ship the machine with extra couplers since this seems to be a common mishap? (and I don't care what anybody says about Axiom's tech support, overnight delivery or not (I have to laugh, because there is NO way that they are going to get to me overnight, since I am in Alberta, Canada, and I would easily wait at least 5 days before I would see that $5 part)). To me, this is the equivalent of a fan belt for a snow blower, or perhaps more accurately, the shear bolts on the auger (which are designed to break off if a hard object (rock, large piece of ice, etc) gets into the auger and stops larger components from being damaged). The problem being, there isn't a hardware store around that sells these couplers the same way that one can purchase the shear bolts (and anybody with a snowblower has a good supply of those shear bolts on hand since those things tend to break when stores are closed).

While I'm on a roll, I have read some forum posts talking about the fact that running the machine too hard/fast can result in less than desirable results (i.e couplers breaking). Correct me if I'm wrong, or out of line, but the ONLY limitation that I have read anywhere is the x-/y-axis feed speed limitation (200ipm). I have played around with plunge rates (I used the Vectric Aspire default rate of 30 for the longest time) and have recently tried ramping it up (in an effort to reduce my cut times). It might seem obvious now that that is what MAY have caused my coupler to disintegrate, but if there is a hard limit (let's say 50ipm for plunging), why isn't it spelled out somewhere (other than saying "Don't run your machine so hard!"). As I mentioned in the first paragraph, I have been running my machine fairly hard (and made mistakes along the way, mostly related to not following my own checklist, or letting the dust collector hose getting caught up, causing lost steps), but I came into this expecting this machine to be able to take a fair amount of hard running (compared to my belt driven ShapeOko with an estimated speed limit of around 40-50ipm, or my Pirahna, which has a limit of 100ipm). I tend to think that many people are "babying" their machines, and if that is one's nature, fair enough (especially if it's only used for hobby purposes), but if a person expects to make money (my goal) using this machine, babying the machine isn't really an option. I have no desire to get a bigger machine (i.e industrial production specs), and I'm actually already thinking about a second AR4Pro (since you can only carve one project at a time, and some of my run-times are in the 10-12 hr range), but if I'm always worried about a simple coupler disintegrating, I may have to re-think about going with Axiom and looking elsewhere.

Attachments:

[stevem]

Don't know what's happening, but I have had my machine for a year now and no broken couplers.
I have not run the machine faster than 150 ipm. I never have my plunge rate that fast.
You're really only saving a few seconds by running it that fast.
If you really wanted a machine that cuts at 300-500 ipm, you should have bought something else.
I remember you and I talking about this when you were thinking about buying the Axiom and I am sure I told you the same thing.
These are more of a hobby machine! And a really good one at that. But wanting to run it that fast all the time may not be the best thing to do.
For the money, this is a great machine.
If you really want to run it that hard all the time, I believe I said to look at a Camaster or ShopSabre. Probably in the $12,000 range and possibly more, but very heavy duty.
That all being said, if $5 couplers are the only problem, just make sure you have some in stock and all is good.
Sorry to hear you are having problems!

[stevem]

Another thought is with the type of detailed work you are doing, a second machine may be your best bet. Your badges look fantastic and if you're making that many, a second machine would allow you to slow the machines down a little and still be able to come close to doubling your production.

[aluomala]

Mar 3, 2018 23:23:12 GMT -5 stevem said:

Don't know what's happening, but I have had my machine for a year now and no broken couplers.
I have not run the machine faster than 150 ipm. I never have my plunge rate that fast.
You're really only saving a few seconds by running it that fast.
If you really wanted a machine that cuts at 300-500 ipm, you should have bought something else.
I remember you and I talking about this when you were thinking about buying the Axiom and I am sure I told you the same thing.
These are more of a hobby machine! And a really good one at that. But wanting to run it that fast all the time may not be the best thing to do.
For the money, this is a great machine.
If you really want to run it that hard all the time, I believe I said to look at a Camaster or ShopSabre. Probably in the $12,000 range and possibly more, but very heavy duty.
That all being said, if $5 couplers are the only problem, just make sure you have some in stock and all is good.
Sorry to hear you are having problems!

I didn't break any couplers on my other machines, no matter what I did to them ( I made LOTS of mistakes, and experimented with ridiculous values for feeds/speeds), and they are most decidedly hobbyist machines (the first under $1000CDN and the second under $2500CDN).

I'm not sure if I missed something somewhere, but Axiom markets these as "Pro" models (it's right there in the model name), and from their description on their website it states: "...compact industrial machine....".

I realize you tried to steer me in what you considered to be the right direction, but I had purchased my machine, sight unseen, prior to your advice, based on a friend's recommendation (he had the coupler issues, but he is also running the machine in the same manner as I am (almost exclusively 3D carving)) and what research I could do online (where I am, small factor CNC machines aren't available for demonstrations, so I rely on forums, YouTube videos, reviews, etc).

I think that your attitude of "if $5 couplers are the only problem...." is giving Axiom a pass on their design, QC/QA and tech support issues. If my Ram truck blew an axle every time that I decided to take it slightly over the speed limit (or under the speed limit, since I don't think I didn't really go "balls out") , FCA would be out of business (and likely the subject of a class action law suit). I understand that there are faster, beefier models out there (there's always faster, beefier anything out there), but when I have an issue with a machine that is billed as a "compact industrial machine" over said $5 coupler (and many other people have had the same issue, let alone other issues, such as wiring harnesses being hooked up wrong (link); missing set screws (for z-axis coupler) right from the factory/warehouse (link) so a brand new machine is useless; lack of decent documentation/resources (if this is really a hobby machine, a complete noob, with no CNC experience would be completely screwed trying to uncrate the machine, create a project, and cut it (as some of the forum posts illustrate very clearly). In this day and age, video tutorials are provided for EVERYTHING you can buy, so I'm not sure why no such thing (officially) exists for newbs (or someone coming over from another platform). I have half a mind to create a tutorial (based on what I have learned, on my own), but a) I don't have the time, since I am trying to run a business, and b) it's not an end-users responsibility to create something like that: it's the job of the company creating the product. And please don't mention the training they provide: I live 2000 miles away, so it's more than a little unrealistic for me (and anybody else really who doesn't live near their business HQ) to attend a training session, particularly when we live in the age of teleconferencing, Skype, YouTube, etc (distance learning)).

I don't really want to crap on you, since you are very helpful and have good intentions, but defending a company/product line as staunchly as you have is a little unnerving (to me, anyway). I have to admit, I have been impressed with many aspects of the machine (compared to my experiences with my first 2 machines), such as the breakpoint and pause functionality (granted that is more controller-based than machinery based), and the fact that the spindle seems to be bomb-proof (and did I mention how quiet it is?!?). It's just the few "but..." issues that I'm concerned with, and to be honest, they could be easily addressed. 1) Be more honest/forthright in advertising/literature with regards to  capabilities and limitations. 2) Create better documentation, so that a beginner can go from zero to hero without leaning on the forums (or calling customer service/tech support) for every step. 3) If you realize that there is a design flaw (couplers?!?!), do something about it. Whether that's buy a crap-ton of them and mail them out to your customers so that they have a stock of them for the possible (inevitable?) failure, or source better quality parts (if all the fancy bells/whistles stuff (controller, spindle, gantries, rails, ballscrews, etc) cost so much, what's a few bucks more for better couplers?!? Or "throttle" the machine so dummies like me can't break the thing within 2 weeks of owning it (and believe me, I don't think I am "abusing" my machine, with rough passes at 80-100ipm and 1/2 diameter (of bit) depth of cut, and finishing passes at 125-150ipm). If it's truly "industrial", that is a light jog, not a heavy sprint.


Allan

[aluomala]

Mar 3, 2018 23:30:58 GMT -5 stevem said:

Another thought is with the type of detailed work you are doing, a second machine may be your best bet. Your badges look fantastic and if you're making that many, a second machine would allow you to slow the machines down a little and still be able to come close to doubling your production.

Up 'til today, I was really leaning towards a second AR4 to do just that, but I figured that I would avoid the coupler issue, since I wasn't really going crazy on my feeds/speeds (yet). I don't want to have that nagging "what if...." feeling about buying a second machine that has the same issue(s). I'd rather buy another brand that is more reliable, even if it is more expensive. If I can find one (I haven't started looking yet) that uses the same controller (lack of learning curve for new machine, and ease of switching between machines between projects), I will definitely think about going that way. Or selling this machine, and buying 2 of the same model from a different company. That's the worst case scenario, but I need to have contingency plans.

[ricphoto]

Allan...Thank you for putting in writing what I'm sure a lot of us are feeling...We've all experienced the impact of the lack of documentation, "creative" marketing specs/tactics and unrealistic shipping promises...

My woes continue as I accidentally discovered that my bought and paid for Rotary attachment has slipped it's promised shipment date for the 3rd time...no notification from the company though...I had to read it on the product page and call them...They charged my card over a month ago, told me it had shipped then told me a few days later that it would be 2 weeks...nothing from them since until I called last week and was told it would now be April sometime...Guess once they have your money it ceases to be a problem for them...

of course those who do have the Rotary can't use it because there apparently isn't any documentation for it...Why buy a $1000.00 attachment if you can't get it or can't even use it when you do?

Bottom line is there doesn't seem to be many "Brand Ambassadors" being created...

[garylyb]

I found a piece of hard red plastic on the floor. it was from something circular, but I didn't know what.

I'll go out and check the coupler in a few minutes.

[stevem]

I guess that Axiom being a smaller company, they still have work to do regarding fixing issues like couplers, a better and more understanding manual and items.
A few days ago, I was on line and saw some videos from Laguna that use the same A11 controller we use on these machines. The Laguna is a similar machine, but because of the size of the company, they have the ability to come up with some decent video's that explain how to operate the controller better than our manual.
Hopefully, sometime in the future Axiom will get there!
As for the coupler's, I agree they should be supplying a better product. There are many Axiom customers that have had to replace these far too often. The design seems to be weak or designed to actually break, before something more severe breaks on the machine. I really don't know if it's really in the design, but if it is, they should supply the machines with extras so they can be easily replaced.
I never saw Axiom address this machine as a small format commercial machine, but if they are, that may be a mistake on their part.
When I bought mine, I compared it to the Next Wave HD4 that I had just bought and couldn't keep it running. I thought it was a fantastic machine for the price. If I were going to rum a business like you are, I think I would have looked elsewhere for a machine. I remembering you saying you bought the machine sight unseen, which is a tough thing to do. These things aren't cheap toys to just throw away after we're done playing with them.
From what you are making, which looks like mostly v-carving, I agree you shouldn't be having problems like you're having.
If you are looking for another machine that uses the same type of controller, the only other machine I have seen is the Laguna. From reading reviews on there CNC machine, it looks more like a cheaper version of the Axiom. I originally looked at the Camaster before I bought the Axiom, but because of the price difference, I simply decided I couldn't justify the cost.
Most of the other machines don't have the controller we use. You would need a computer hooked up to the machine to run it. That is why I bought this machine in the first place. Now that I have this machine, I am starting to think that having a machine connected to a computer wouldn't be the worst thing in the world to have. I find myself changing thing at the last minute and have to keep updating my usb stick to run the project. The only good thing about that is I can have my laptop sitting on the bench and just update it next to the machine.

Anyway, sorry you are having these problems Al.

I wish money grew on trees so if we didn't like something, we could just throw it away and go get something else. With my very small woodworking business and the fact that almost everything I make, I don't need need the use of a CNC machine, I have to just do the best I can and enjoy the machine I have.

[garylyb]

Well, I checked the coupler, and mine is fine. I still don't know where the plastic came from.

I've had this machine for about a year and a half. There was a loose wire when it got here, but since then, I've not had much trouble with it. I used to cut a stack of 2 pieces of 3mm aluminum skinned plastic. That caused problems with the x-axis, but I now cut 1 2x4 foot sheet with no troubles.

I make clocks and can cut 8 clock blanks out of a quarter sheet of 3/4 MDF at 200 ipm with no problem. I run the machine almost every day for a little while, but I don't do 3d carvings, so each job is minutes long, not hours.

I agree it doesn't sound like you should have had trouble with your coupler.

[traindriver]

Not taking up for anyone, just thought I'd post my experience with the couplings.  I've had my machine for 2 1/2 years, and while I don't do 3d models every day, I have done probably 30 or 40 - the longest one took 30 hours and was 18 x 18. I know my feed rates have been conservative, but I am still using the original, old style couplings that came on my machine before they went to the "lovejoy" style couplings. I read on this forum that people heard a clicking noise from their Z-axis and shortly afterward, the coupling broke. I suspect that the reason their couplings broke and mine hasn't is because I don't use the puck to set my Z depth and perhaps when their bit hits the puck, it's a little too hard. I attempted to use the puck one time when I first got the machine. I didn't like it, and have set the Z->0 the old fashioned way using thin paper ever since. After crashing my Z axis a few times, I started hearing the dreaded clicking noise and upon close inspection, found that my coupling is cracked, so I ordered a new style replacement. That was a year ago and I have yet to replace the coupling. I realize I'm cursing myself by admitting this, but so far, so good. My plunge rate is at 30 ipm, by the way.  If you can find out what the torque rating of the motor is, McMaster-Carr has a variety of couplings with their ratings here and you may be able to pick a better one.  

[stevem]

There is info on one of these threads that explain how to adjust the Z axis when using the touch off puck. Mine was set at 600 when I got the machine and I now have it at 150. When zeroing the bit, it very gently touches the puck before retracting. Perhaps that is why aluomala and others are breaking their couplers. So far, mine seem to be fine, but who knows.

These are the instructions on how to adjust the touch off speed.

Press MENU
Select Auto Pro Setup
Press OK
Scroll to find Toolset Speed
Press OK
Press RUN/PAUSE DELETE to enter a new number
Enter the number
Press OK
Press OK
Press Stop/Cancel
Press Stop/Cancel

The default number is 600.  Way too fast.  Will break delicate bits for sure!

[gerry]

I have my touch off seat to 150, also. It's slow, but I eye ball it pretty close next to the puck, then move the puck under and touch-off. Works like a charm, and it's still very quick.

[trung999]

The type of circuitry that triggers a retraction of the bit upon contact with the puck can issue a signal in a matter of milliseconds due to an avalanche of electrons the instant the bit interacts with the puck. If the bit moves down slowly it should be able to stop almost instantaneously (I position the bit ~10mm above the puck before sliding the puck in). I was concerned with minutely damaging the surface of the puck leading to inaccuracies over time so tested it out. I put the puck on a soft bed of towels to observe the movements during touch offs. There was nothing observed. If I lightly held the puck only a slight sensation can be felt so I think the operation can stay quite reliable over time.

For some reason the Axiom puck is 5mm taller than garden variety puck you can buy to replace, but that's easy to remedy.

[redwood]

I have also had my AR6pro for 2 years now. I still have the original coupler on my X axis, but the Y and the Z couplers broke. They were quickly replaced by Axiom with the newer style. Knock on wood, I haven't had any issues with the new couplers. I do have a spare, so that if and when I need one, I'll have it.

I have always used the puck for Z height calibration. I'm very conservative with my speeds, but the machine has be run a lot.

[stevem]

You wonder if quality control is the problem!
I am sure Axiom doesn't actually make many of the parts on their machines. They are probably off the shelf items that are available almost anywhere. You just have to know where to look for them. So when they install these coupler's, and many other components, they aren't checking them beyond a visual inspection. That's why there are things like loose wires, plugs falling off and many other things happening to these machines.

Then shipping these things, they get bounced all over the place, are put on a container ship and come to the U.S., get put on another truck and are bounced all over the place again before they get to Axiom in Ohio and are unloaded again. Then they get put on another truck and are bounced all over some more and get delivered to us.
It's really amazing to me that they don't have more problems than they already have.

Even companies that build these CNC machines in the U.S. have similar problems.

[Axiom Tool Group]

These couplings were upgraded from a previous more spring like model, in which we had seen lots of breaking due to wear. The metal of the coupling simply could not take the flexing.

With the current coupling, which have been in use for near two years now...these are considered a LoveJoy style coupler...where the polyethylene bushing is absorbing the shock of directional changes and any minor alignment differences between ball-screw and stepper motor shafts.

These are meant to be unbreakable at the torque levels seen on our machines.

That said, to be honest, recently we have replaced less than a dozen or so due to that polyethylene bushing breaking.

We do not believe it has anything to due with the operation of the machine....more concerned that a flaw may have be present in the bushing. At this point its impossible to say for sure. But over the years we have been using them, there have been no problems until just recently.

When preparing machines for shipment and performing our tests, we use our own coupling so we leave the customers coupling new in the packaging with the stepper motor.

With the recent issues with coupling breaking, the Z-axis coupling is now going to be installed on the machine and left in place for shipment. Allowing us to make sure that both screws are present and that the bushing is in one piece.

We do keep an inventory of couplings for warranty replacement. Customers with broken parts should contact us immediately.

Personally I like the idea of including a spare coupling in the machines, though with the number of machines shipping...we may need to make some changes as presently I do not have that many spare couplings on hand and it will take some time to get additional parts here.