PDA

View Full Version : The pulley is broken, Captain!! ..How do we steer?



Joseph Belangia
03-01-2011, 10:42 PM
Dang....

I was running a job today when the sails broke...well, to be more specific, the belt pulley on my "Y" axis rung its own neck. I say "Y" axis, because apparently in Vytek's world, up is down and black is white....X is Y.

http://farm6.static.flickr.com/5058/5490769318_99c8bb6c2c_b.jpg

Obviously the support wasn't very supportive. I didn't buy my machine directly from them, so I'll spare you the details on their "support" program as I'm sure many of you out there are far too familiar with that song and dance.

As you can see, the collar that the clamp attaches to just wore the hell out and snapped. Anybody have any suggestions? 25-tooth pulley on a LIN Engineering motor 417-15-03 1.2a

Bruce Boone
03-01-2011, 11:26 PM
Check with W.M. Berg company. They have small drive components like that. You'll need to know what the pitch of the belt is, but it might say on it. You could also measure with calipers to be sure you're getting the right replacement stuff.

Bruce Boone
03-01-2011, 11:41 PM
Also these guys: Stock Drive Products http://www.sdp-si.com/D265/D265Cat.htm A search for "metric timing belt pulley" will pull up more. Nail down the pitch first to know if it's metric or English. I imagine it's metric.

Richard Rumancik
03-01-2011, 11:43 PM
There are various companies that make timing belt pulleys but the one you have may very well be a special. Maybe Small Parts Inc, Stock Drive Products, Allied Devices, Nordex Inc. They may be able to machine or modify one but it won't be cheap.

The best solution is to do what is necessary to get the right part from Vytek.

But it may be possible to rework this one if you are in a pinch. Rebore the pulley to the same diameter as the OD of the piece that snapped off. Then make a hollow-shaft steel insert to match the geometry of the original. Press fit or Loctite it in place. Would be cheaper than making one from scratch.

Did the piece that snap off have a longitudinal slit in it? I see what looks like a clamping collar in the back; I assume it must be used to compress the exposed collar and assume it had a slit to allow compression.

Joseph Belangia
03-02-2011, 12:53 AM
Exactly, Richard. Compression slot and then the clamp goes over. Would have been sturdier if out of steel, but this was aluminum, so it just wore slap out.

Thanks for the helpful info!!

Mike Null
03-02-2011, 5:36 AM
Along the same line as Richard's suggestion...

I think I might try a machine shop and ask them to have a go at inserting a brass bushing and then have a go at some adhesive such as loctite. If need be, I assume a new collar could be purchased to match the bushing.

http://www.asbbearings.com/

Joseph Belangia
03-02-2011, 10:18 AM
I like this idea, guys. ^^

The more I researched what I was looking for utilizing your help, the more I realized that:

A.) I'm not dealing with Vytek. The mafia has better service plans.

B.) Anywhere else I go will have to have it custom machined. That's a set-up fee, one-off price, yada, yada...

C.) Re-boring the center and press-fitting a sleeve would be drastically cheaper.

D.) I'm not dealing with Vytek.

I'll keep you updated as things progress. I need to have this sucker up and running pronto.

Thanks again for all your help. Love this place.

Scott Shepherd
03-02-2011, 10:29 AM
They won't sell you a pulley and belt?

What's the deal there? That's kind of important information to know before buying a machine. If they won't support their machines, why would I buy one? (not you Joseph, but in general)

James Terry
03-02-2011, 1:25 PM
Perhaps this previous Zsolt Paul (http://www.sawmillcreek.org/member.php?38734-Zsolt-Paul) could help you out with his experience last month?

http://www.sawmillcreek.org/showthread.php?159996-Replacement-parts-for-vytek

Richard Rumancik
03-02-2011, 2:37 PM
Joseph, if you go with the insert idea I think Loctite is safer. Once the end of the "tube" is slit in two axes, then pressfitting might be a bad idea.

The other option is to pressfit/Loctite a solid pin and then bore and slit afterwards. Discuss with a machinist and see what they suggest.

But sooner or later you may need something from Vytek so best to keep that channel open.

Richard Rumancik
03-02-2011, 2:47 PM
I looked at the link to Zsolt's post. Yes, maybe $75 seems like a lot for a pulley, but I have had to buy parts for my car that cost much more than what would be expected, too. And parts for cars are made in quantities thousands of times greater than laser system parts. Sometimes you just have to grit your teeth and get out the charge card. Realistically, if a pulley costs $75, it is still probably cheaper than modifying or reworking, given that it will take a lot more time and handholding as well. I'm not defending Vytek in particular as I don't know the exact situations quoted here, but most laser replacement parts will be more expensive than you might guess or hope for. That is the cost of doing business with these machines. Parts wear out and things break and fail.

Joseph Belangia
03-02-2011, 10:35 PM
All great points, gentlemen!

I'm not going to leave you hanging, so here's where we are(Paul, check this out and see if any of this is applicable):

Vytek....is a little bit different. Great machines, don't get me wrong. They are awesome, and would buy another if needed. Obviously I do not want to come across as slanderous, but I do want to share my experience in the most honest way without stepping on any toes, as Vytek has stepped up and done the right thing in this case and I want to give full props to them for doing so. But you do need to know how to navigate those waters.

If you did not buy your machine from them, then you will need to pay them $125.00 to register your system with their database. So far, that's not an unreasonable request. I get that, no problem. A little steep, but whatever...let's just move on with it.

Here's where the issue comes into play for me....and believe me, I have examined the issue from their side, so any responses hereafter explaining said principals will have the potential to fall on my selective hearing-impaired deaf ears. I get the basic principals of business, I do....let's focus on doing the right thing, not what the SOP says to do.

You also need to open the wallet up a wee bit wider to fork out another $225.00 per year for the privilege of ordering parts from them, getting repair advice, or just speaking with them on the phone--but the phone-speaking part will be billable at $75.00 per hour. A $10 part that is marked up to $50.00(still no problem with them making a buck on parts....love capitalism!) now has a 125.00 and 225.00 set of ugly friends coming along with you on your 50-dollar date. I went to college....the ugly friends ruin EVERYTHING!

So you can start to see how one might feel that they.....as an occasional parts-buyer....are starting to feel strong-armed into some unnecessary B.S. that is now taking the form of an uncomfortable customer service experience. Always adhereing to the principal taught by grandma that one catches more flies with sugar than with vinegar, I contacted a sales rep from Vytek and began a dialogue that I'll distill down to the essentials.

Having explained to the sales guy that my experiences with their machine has been very user-friendly and that the reliability has been rock solid, I was very disappointed that the same experience did not extend down the line to the customer service end of the deal. As a fairly mechanically-inclined individual, I have no problem getting into the nuts and bolts of the problem, identifying it, and then buying the part to fix it. Give me assistance in doing so along the way with sales of said part and you have a customer for life. Doesn't take Warren Buffet to work out that business plan.

Obviously the sales guy has to tow the corporate line....I get that, but where's the love? Don't whallop me about the head with all of these fees. I watched the Charlie Sheen interview, I'm a winner too! My faith in humankind was given a second chance at life when I wished our sales guy a happy day as my next stop will be the machine shop to have 'em work out a press-fit situation which I knew would work just fine. At this point, it will still cost less than what Vytek was going to tan my hide with on these fees. Common sense must have realized that it had overslept and dashed down the street in its PJ's to meet the sales guy as I'm sure he had a moment where he realized "Hey...here's a guy that isn't afraid to jump in there and do half of our work for us and diagnose his own problem, find what he needs and contact us for it. We don't have to waste time going over laser 101 over the phone, we can make money off the parts he needs and everyone is happy."

The next message I receive is from the rep letting me know that the $225.00 fee had bee waived and they will sell me the part if I agree to register my machine with their database. I'll take the $175.00 over nearly $400.00 any day. As I mentioned above, I get the registration fee....not stoked on the price, but I understand that and have no problem absorbing that one-time fee, but once you start chirping at me for larger stacks of my dough, then I've got to chirp back and ask that you look at the situation and just do the right thing. They did, and I'm cool with it.

So tomorrow I'm going to call and register my weapon with the sheriff and order my part. I still took my other one down to the machine shop and are having them run me one with a press fitting as a back up.

Thanks for following along and offering your suggestions. I take all of them seriously as you guys(and gals) are some seriously smart folks!


Edit: Here's the photo of what the pulley looks like assembled and associated part numbers and pricing. You can see how that small neck on the pulley just wrung off on mine as it was underneath the bolted collar.
http://farm6.static.flickr.com/5217/5493463378_355d2f0e88_b.jpg

Bruce Boone
03-03-2011, 12:11 AM
Obviously the clamp and motor notations are reversed, but it does look to be a rather poor way to hold onto a pulley from here. The huge change from thick to thin and squared off corners in the slots are stress risers calling out for help. Worst case, it looks like you could drill and tap some holes for setscrews to clamp onto the motor shaft right through the side of the pulley. The belt should ride right over the holes as if they weren't there.

Dan Hintz
03-03-2011, 7:41 AM
I'm with Bruce... if it were me making that part, at the very least I would have put a fillet on that necked down portion of the pulley. Ideally, I would have milled two flats on opposite sides of the motor's shaft and used a simple set screw for good measure.

Joseph Belangia
03-03-2011, 8:40 AM
It's funny how when we take these things apart, the engineer in us all starts to take over just a bit. Doing some research on the motor manufacturer shows plenty of spindle options that would all cure this obviously weak point in a critical junction, but unfortunately, this is the option they went with. The piece I'm sending out to the machine shop will have just such an interface, so I'm confident that if I ever encounter this situation again I'll have a solid backup part.

Richard Rumancik
03-03-2011, 1:27 PM
Yes, it is easy to say that they could have . . . should have . . . but in real like it is not always that easy. The smooth shaft option was off-the-shelf. The one with flats was 8 weeks lead time and double the minimum quantity. Plus more expensive. After the prototype, the engineer wanted to change to flats, but by that time purchasing had ordered 9 months worth of motors and 12 months worth of pulleys and 18 months worth of collars so they could meet deliveries and cost targets. Okay, I just made this all up, but that is the way it often is in reality.

Perhaps the split collar geometry was not well-implemented; it is not an uncommon method but works better in steel. Setscrews have their own problems. (BTW, if you rework the old one to use 2 setscrews, make them 90 degrees apart.)