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  #31  
Old Fri 04 April 2014, 18:04
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
Add that to the low cost of the software to generate your gcode. 3k + 5k = 8k. Or you could build another Mechmate when your business need justifies it.
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  #32  
Old Fri 04 April 2014, 20:06
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
You are right, but if it can make it for less...now we're talkin'. I don't really see the need for anything I do though. The videos of a 5 axis Thermwood on youtube shows more in line of how I'd want mine designed. Looks more solid. I just don't understand the cabling set-up, you'd think it would twist right off but maybe the software is aware of that.

So true Pete, but you'd still have a 3 or 4 axis machine.
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  #33  
Old Fri 04 April 2014, 20:22
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
It can be done
https://www.youtube.com/watch?v=nITLI_WcnuM
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  #34  
Old Fri 04 April 2014, 22:03
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Very nice machine. I think it is designed to cut only foam. Light like a electric foam cutter.
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  #35  
Old Fri 04 April 2014, 23:06
racedirector
Just call me: Bruce #122
 
New South Wales
Australia
Heres another one on kickstarter.....

https://www.kickstarter.com/projects...r?ref=category
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  #36  
Old Sat 05 April 2014, 05:20
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Yep, but I don't do foam. There's no way that kickstarter machine could work on wood, It'd be all over the place from flex.

Sorry Darren, we've somehow taken over your thread...Next subject please...post something you've done recently...thanks

Last edited by Tom Ayres; Sat 05 April 2014 at 05:23..
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  #37  
Old Sat 05 April 2014, 09:38
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
Sorry Darren, we will move this to Tom's thread
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  #38  
Old Sat 05 April 2014, 12:16
darren salyer
Just call me: Darren #101
 
Wentzville mo
United States of America
Its all good.
Been under the weather the past couple weeks, so no new pics to post.
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  #39  
Old Wed 09 April 2014, 21:02
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
Tom, I believe the the DoughtyDrive is using a planetary gearhead with positive drive belts. If it was a harmonic drive, I can see the Zero backlash statement but the site says 30:1 with + - 20 arc seconds. This would lead me to think it is a planetary reduction. The NEMA 24 stepper would be fine with that much reduction.
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  #40  
Old Wed 09 April 2014, 21:05
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
Maybe the easiest avenue that would be the most useful for smaller detailed parts would be a trunnion. You could make detailed roses and other items that I think would be more useful to the woodworker. Anyone here ever venture that route?
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  #41  
Old Thu 10 April 2014, 02:51
Quadro
Just call me: Anthony #77
 
South Australia
Australia
5 axis is achievable, the plasma one i designed it to be able to take a 1.5kw square air cooled motor as well. The bearings I used were ball bearing, if it were to be used with a router I would up grade it to tapered bearings.

The CAM software is the one of the main hurdles.
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  #42  
Old Thu 10 April 2014, 04:20
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Pete its obvious that I need to learn a lot more. But what makes the planetary drive better than the harmonic drive? I haven't seen a "positive belt" yet. Do you have any visual references of the differences?
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  #43  
Old Thu 10 April 2014, 04:33
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Oh, a trunnion bed was my first thought but is very limited to size. I have seen them being used for milling engine blocks and porting heads. Not really the direction I'd want to go.
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  #44  
Old Thu 10 April 2014, 17:16
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
A harmonic wave drive is better as it is truly Zero Backlash. Planetary is always in the arc seconds or minutes depending on the quality. Harmonic drive is the way to go but finding a reduction from 10:1 to 50:1 is hard and expensive. That is why most opt for planetary gearheads. Too much reduction and your speed to torque ratio becomes a factor.

The trunnion would be suited for most people unless you are building a large scale model in the feet range.
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  #45  
Old Thu 10 April 2014, 20:30
ger21
Just call me: Ger
 
Detroit, MI
United States of America
I think the best (cheapest) approach is to study all the products available from a manufacturer like Harmonic Drive, and design around those components.
http://harmonicdrive.net/

Then watch Ebay constantly and hope what you need turns up. Expect to pay $250-$500 each minimum. Also expect some rather complex engineering, and some custom fabricated parts.

Realistically, though, a 5 axis router is really good at certain things, but below average at most other router tasks due to a lack of rigidity. Unless you have a steady flow of work that requires a 5 axis machine, the only reason to build one is for the cool factor.
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  #46  
Old Fri 11 April 2014, 05:09
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
I agree with Ger. We have a Haas VF6 with a trunnion at work. Great machine that is underutilized. I see the most useful items that a 5 axis can make are small items. The super large stuff is rare and in a specialized field. The small items are added to your existing product to give the wow effect.
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  #47  
Old Fri 11 April 2014, 06:42
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Ger Thanks for the link, lots to chew on.

What are the common sizes for these trunnion beds? Or should I ask, what is the most useful bed size in your opinion? Are we talking a 4" x 4", 8" x 8", 12" x 12", bigger?
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  #48  
Old Sun 20 April 2014, 17:57
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Well, had a little time to look into the harmonic drives that Pete had mentioned. Found that there is another world out there that needs to be explored. I'm intrigued and very interested in doing a 5 axis but will report back when I have a better grasp on some ideas.
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  #49  
Old Mon 21 April 2014, 09:39
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Not to throw water on the fire, but if you build a 5 axis machine, how many times do you think that you would get some one that would want you to cut some thing that requires 5 axis machine and would they be willing to pay what it cost? Yes, it would be fun to own one but how often would you use it?
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  #50  
Old Mon 21 April 2014, 10:16
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
It's not about the use, if it's available jobs can be found. It's more about the challenge and discovery to me. We all can try to justify doing something like this for whatever reasons, but how many do it just to learn something beyond our norm, few. I've always sought challenge over practicality (if I could afford to do so), I agree not always wise though. But right now I can at least give it a little attention for curiosity sake.
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  #51  
Old Mon 21 April 2014, 10:47
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
If one does decide to upgrade the MM platform with a b/c head, think about the extra mass and uplift on the y-car. I would suggested adding a second drive motor and gear rack to the hold down side of the car. The extra mass and extended moment arm is a bit for one motor to handle.

I almost added a second y motor on my extended slide MM #5 for this exact reason.

Not a huge cost, but a consideration while your pondering the future!
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  #52  
Old Mon 21 April 2014, 12:19
Fox
Just call me: Fox
 
Amsterdam
Netherlands
If that will be the case why not just use a stronger motor !? Saves the extra expense and hassle on rack, gearbox driver etc. .... the y is not that far apart tot worry about tilting IMO.
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  #53  
Old Mon 21 April 2014, 12:27
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Fox,
You could use a bigger motor and larger amplifier.
But, if you were upgrading your current machine, the G203 and PMDX allow for "step sharing" on the output of the card might be an affordable solution.

Good points made by all.
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  #54  
Old Mon 21 April 2014, 16:41
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
That is why we have a mind, to think, dream, create and enjoy!
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  #55  
Old Mon 21 April 2014, 19:14
darren salyer
Just call me: Darren #101
 
Wentzville mo
United States of America
Related to Walt Disney, Nils?
I like that quote.
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  #56  
Old Mon 21 April 2014, 20:26
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
I truly believe a trunnion addition makes more sense than having the spindle position itself. I can see the market for small intricate items more than the large. It cost of making the trunnion would be small compared to the cost of the software to program continuous machining.
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  #57  
Old Fri 25 April 2014, 13:08
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Well here is a 80:1 Harmonic Drive gear I got from Ebay this week, new old stock, I couldn't really retrieve any specs on it in the short time it had left in the auction but got it for less than $27.00 delivered (couldn't take a pass on it if it would work). All the others run $399 and up, most of the larger ones around $1k I'm not sure I'll be able to use it for additional axis, seems small, only 2.75 inches.

Well if I can't use it for this I'll use it for gear reduction on my bead roller build I will one day complete. (or relist on Ebay for some profit, lol)
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  #58  
Old Fri 25 April 2014, 14:34
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Oops I forgot to post the picture of the drive

Last edited by Tom Ayres; Fri 25 April 2014 at 14:38..
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  #59  
Old Fri 25 April 2014, 18:03
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
Size is fine, with that much reduction, the torque will be great but your speed will be slow. You will be at the high end of the stepper speed so the stepper torque will drop off. I would not be afraid to try it. You will have a little time in designing a mount for it with a seal. Looks like you made out well.
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  #60  
Old Fri 25 April 2014, 19:38
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Pete, you are right, lotsa torque, I was hoping it was going to be 30:1 but no such luck. Heck it could be an indexer gear if nothing else. Of course, after getting this in the mail today I looked on ebay and found a bunch more with the motors which I didn't find on a previous search, oh well, I still got a deal. Its a pretty cool gear set-up.
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