Thanks, Bud. There's more info and video on our site, www.bell-everman.comOriginally Posted by RCXPLANES
We've had very good response to this product, and we've gotten 5 design wins with it since introducing it in July. I'm not forgetting kit level sales at some point for the DIY'ers!
Mike Visit my projects blog at: http://mikeeverman.com/
http://www.bell-evermannews.com/ http://www.bell-everman.com
It's a very nice design! I just saw it posted on cnczone.nl (dutch version) and i really like the way it works. Very simple.
I saw in your PDF files 0,01mm(?) acuracy, which is impressive!
But is it going to compete with ballscrews? even C5 and maybe C3? Or is this for speed and people who want it. I like it because it would eliminate the need to build any type of bearing houses.
Thanks, Jfwiet.
No, not much competition for ballscrews in short axes, where stiffness is a priority. This is built for speed, and long travels that a ballscrew could not do, and more competition for racks and Nexen type drives.
Mike Visit my projects blog at: http://mikeeverman.com/
http://www.bell-evermannews.com/ http://www.bell-everman.com
pricing hint for diy-ers interested in a kit? say in a month or so...
I'm looking to build a 60" by 40" wood cutting machine early in the New Year.
I love the look of this stuff!
Will it be compatible with 15 series 8020? (1530 in particular since i've already purchased a bunch)
Thanks!
Sorry, no pricing hints possible at the moment.pricing hint for diy-ers interested in a kit? say in a month or so...
I'm looking to build a 60" by 40" wood cutting machine early in the New Year.
I love the look of this stuff!
Will it be compatible with 15 series 8020? (1530 in particular since i've already purchased a bunch)
Thanks!
It is designed around 45mm series t-slots, and I don't think it will work on 8020, if it's the style that has the t-slot legs bent down.
Mike Visit my projects blog at: http://mikeeverman.com/
http://www.bell-evermannews.com/ http://www.bell-everman.com
T5 meshing
Hello Mike,
Interesting concept, not to say brilliant,
I downloaded the CAD drawings of a T5 belt, and the belts do not mesh exactly, there is about a 0.5mm gap between teeth´s sides,
How does this affect backlash? or do you just preload one side of the carriage to one side, and the other side to the other?
Keep up the good work!
Fernando
Hello Fernando, and thanks!
Yes there is a bit of clearance. Tensioning the belt by pulling up the motor and locking it in place removes the clearance and puts the belt teeth in pre-contact under the first, inner idler rollers.
So, you would not want the upper belt tensioned at the ends, or this benefit would not happen.
Mike Visit my projects blog at: http://mikeeverman.com/
http://www.bell-evermannews.com/ http://www.bell-everman.com
Hey Mike!
A couple of questions...
Seeing that your business is mainly pick and place related stuff, do you know of any comprehensive resource like this one (cnczone) for machine vision based pick and place?
something like this:
http://www.youtube.com/watch?feature...&v=AfUlQRkh0jo
and another question...
I saw somewhere on your website that your concept is patented..
What exactly is it that you are patenting in your servo belt drive?
Best regards
Fernando
Hello Mike,
Interesting concept, not to say brilliant,
I downloaded the CAD drawings of a T5 belt, and the belts do not mesh exactly, there is about a 0.5mm gap between teeth´s sides,
How does this affect backlash? or do you just preload one side of the carriage to one side, and the other side to the other?I understand how backlash is removed from the two mating belts. What I don't understand is how backlash is eliminated from the Motor pulley and the belt. There must be clearance unless you have special not clearance teeth. The only other way I can see that there is no backlash in the system is that because of high tension, the friction of the belt alone without the teeth engaging is enough to move the truck assembly. But as soon as there is a significant load, the frictional forces will be overcome and backlash will occur.Yes there is a bit of clearance. Tensioning the belt by pulling up the motor and locking it in place removes the clearance and puts the belt teeth in pre-contact under the first, inner idler rollers.
So, you would not want the upper belt tensioned at the ends, or this benefit would not happen.
Just think of a flat belt with no teeth. There is zero backlash.
I am skeptical that there is no backlash under load conditions only because every source of belt drive information I have came across has claimed GT2 belts king for precision positioning applications where little backlash is desired and high load capacity is needed. AT-zero type belts and pulleys, are also desired for precision applications based on information from Brecoflex company.
To tell you the truth I am drooling over the servobelt concept and would be happier if I could get away with T5 belts and pulleys as they are cheaper and seem to be much easier to get a hold of in wide widths.
Can anyone please tell me I am completely wrong so I can be at peace and not worry about getting quotes from companies that don't care about selling their stuff to little guys.
Hmm good question, i was wondering about that myself...
I guess you only rely on the friction of the belt and pulley not to slip and cause backlash.
Well I am definitely glad I am not the only person who was thinking about this. I'm going to do a belt drive like this for my next machine and I am going to use GT2 timing belts from sdp-si or AT5 timing belts from brecoflex, if they respond to my quote request...Hmm good question, i was wondering about that myself...
I guess you only rely on the friction of the belt and pulley not to slip and cause backlash.
You might get more luck calling them directly and asking for a distributor's contact.
It happens with the big companies not interested in us hobbyists...
Good luck!
Hi Mike.
Because of the difficulty of finding timing belt by the metre over here(that's now been located), I wondered if there would be any disadvantage in looping the top belt back over the rollers, so in effect the top belt is just a typical short belt turned inside out
I realise the top belt did have a function in keeping a lot of debris out of the lower one, but that's easily sorted.
John
It's like doing jigsaw puzzles in the dark.
Enjoy today's problems, for tomorrow's may be worse.
That's an interesting idea. So in a sense it would be like a tractor tread. There is no reason that would not work, but I suspect you would not be able to eliminated the backlash between the two meshing belts the same way that the servo belt does unless you got two belts to mess without backlash. That is a pretty good idea now that I think about it.
Yes that could work,
you could remove the backlash between the two belts the same way Mr. Everman suggested just be able to move the motor pulley one belt pitch to tension the section between the motor pulley and the glued belt, then you would need another tensioner to stretch the belt over the idler circuit.
It is the same concept, a little more machining to do, but less belting needed.
Now the thing is, how to remove the backlash between the belt and the pulley's teeth.
from my measurements there is a 0.014" gap between the teeth of a stock pulley and the teeth of the belt on a T5 belt.
Unless you machine that pulley to tighter meshing, we are stuck with relying on friction to eliminate that backlash.
Then again, how many timing belts are used today to couple a servo motor to a ballscrew, there is backlash there too. much less linear backlash though because of the screw pitch.
Any ideas anyone?
Best regards
Fernando
Fernando
How are you measuring the 0.014" gap? Is it when the belt is flat or when it is wrapped around the pulley? This could make a difference.
Cheers
Don
When it is wrapped around the pulley it is about 0.014"
When it is flat the gap measures about 0.021" but this does not affect because you can remove that backlash with the motor pulley adjustment.
Fernando
Have I missed something fundamental in Mike's original set-up ?
As far as I can see, the top belt, outside of the outer idlers, has no function regarding backlash nor tension of the "active" part of the belt.
Once the belt is outside this area it may be completely loose, for all it does. In which case it could be just a free loop over the top, and doesn't even need any further idlers to guide it.
Please explain what I have missed.
John
It's like doing jigsaw puzzles in the dark.
Enjoy today's problems, for tomorrow's may be worse.
The Servo motor actually has to turn the top belt with a toothed pulley in order to get movement.. The backlash in question exists where the top belt is being turned by the servo. If there exists any backlash between the pulley and the belt, you'd in theory have "backlash" in the movement of the top belt on motor reversal, which is ultimately pushing / pulling against the lower belt.. Unless I'm completely missing how it operates. Either way, very cool design, and I'm sure there's an answer coming!
Just thinking !!!
What if you were to put some kind of coating on the pulley about 0.007" thick? Some kind of plating or anodising. Just a thought. It would be basicly the same as making a new pulley to the specs that you want or need.
I know its just a crazy idea but sometimes one crazy idea brings forth other ideas that might work.
cheers
Don
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