Rotozip or Laminate Trim Router for the spindle?

lasershark1
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Re: Rotozip or Laminate Trim Router for the spindle?

Post by lasershark1 » Thu Apr 26, 2012 1:55 am

I just checked my tool bag. I have both the Ryobi rotozip-clone, and the Ryobi router. Likely the same thing in a different case. Both state 26k rpm on the housing. The rotozip style one weighs 2.02lbs, the router model weighs 2.33 pounds. Likely the same guts inside. Seems like it's a beast on current draw.

So, someone here more knowledgeable than me - how would you speed control one of these? Less voltage? I'm not an expert in motors.

minorthreat
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Location: Boston, Ma

Re: Rotozip or Laminate Trim Router for the spindle?

Post by minorthreat » Thu Apr 26, 2012 3:15 am

lasershark1 wrote: So, someone here more knowledgeable than me - how would you speed control one of these? Less voltage? I'm not an expert in motors.
I'm going to use one of these since I have a few lying around
http://www.sparkfun.com/products/9107
http://www.pololu.com/catalog/product/755

You could probably find better/cheaper out there too, depending on what you want to control it with.

lasershark1
Posts: 143
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Re: Rotozip or Laminate Trim Router for the spindle?

Post by lasershark1 » Thu Apr 26, 2012 4:15 am

My plan is to possibly hack the grbl code and control it with grbl... not sure if I can do that tho. I'm very experienced in coding arduino - I havent touched grbl yet though, and I know grbl is not an arduino script, it's in C and uploaded as hex.

But that controller should be able to speed and direction control an 18v brushed DC motor?

orcinus
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Joined: Wed Apr 25, 2012 8:23 pm

Re: Rotozip or Laminate Trim Router for the spindle?

Post by orcinus » Thu Apr 26, 2012 12:19 pm

Arduino isn't a "script". It's regular C++, just like what grbl is written in.
The difference is, it adds a lot of preset and predefined classes, methods and constants that make coding (initially) easier.

What i'm trying to say is - if you're good with Arduino (i.e. do stuff beyond digitalWrite and digitalRead, and can find your way around the registers), it shouldn't be too much of a problem to do some light modifications to grbl.

That said, isn't spindle control (simple on/off) already supported in grbl via an appropriate g command? I could've sworn i've seen someone doing just that in some youtube video...

lasershark1
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Re: Rotozip or Laminate Trim Router for the spindle?

Post by lasershark1 » Fri Apr 27, 2012 3:37 am

It is. I'm talking speed and direction control via a motor controller :)

CptanPanic
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Re: Rotozip or Laminate Trim Router for the spindle?

Post by CptanPanic » Fri Apr 27, 2012 11:06 am

minorthreat wrote:
lasershark1 wrote: So, someone here more knowledgeable than me - how would you speed control one of these? Less voltage? I'm not an expert in motors.
I'm going to use one of these since I have a few lying around
http://www.sparkfun.com/products/9107
http://www.pololu.com/catalog/product/755

You could probably find better/cheaper out there too, depending on what you want to control it with.
2 things, one those motors are AC so I don't think those controllers would work. And less voltage would work to slow it down. There is a device called SuperPID that looks pretty cool that adds closed loop speed control to AC motors, which is cool because if he motor gets bogged down it can add voltage to add torque to keep the speed up. The only problem is it is a bit expensive at $150 bucks or so. Wish there was an cheaper alternative.

orcinus
Posts: 21
Joined: Wed Apr 25, 2012 8:23 pm

Re: Rotozip or Laminate Trim Router for the spindle?

Post by orcinus » Fri Apr 27, 2012 12:35 pm

lasershark1 wrote:It is. I'm talking speed and direction control via a motor controller :)
The only potentially problematic thing i see is the speed. You'll obviously need a PWM pin for that. Not sure if it (or just the corresponding timer) is already being used for something in grbl.

All else failing, you can always add a second "buffer" ATmega that catches the gcode, filters out the speed and direction commands, lets everything else through to the grbl processor, then acts on the speed/direction commands.

minorthreat
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Location: Boston, Ma

Re: Rotozip or Laminate Trim Router for the spindle?

Post by minorthreat » Fri Apr 27, 2012 2:37 pm

CptanPanic wrote: 2 things, one those motors are AC so I don't think those controllers would work.
Good point to distinguish. The 2 roto-tools in the OP are AC, the Ryobi is DC. The 2 h-bridges wil work for the ryobi.

edwardrford
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Re: Rotozip or Laminate Trim Router for the spindle?

Post by edwardrford » Sat May 05, 2012 5:10 am

Hi All, just wanted to report back on my Dewalt Trim router experiment.

Tonight, In between tasks, I managed to squeeze in the new UHMW mounts to accomodate my Dewalt Trim Router. I bought it from amazon about a month ago for about $55. Delivered. (Here's the link).

I used the same material to make the mount (3/8" white UHMW) and mounted it the same way as the dremel (bolts into insertion nuts, slid into the z-axis extrusion). There is an issue with my design that didn't accomodate an M5 x 10mm bolt and was too long for a M5 x 16mm bolt, so I had to use washers between the mount and the extrusion to make it work. Not the best scenario, but it seemed to work. I'll try to get the revision done to the parts and post the mount for anyone who is interested in giving it a try.

A couple of random notes:
- It's bad ass! (for lack of a better phrase) Plain and simple. Going from a 1A rotary tool to a 5A is like night and day.
- I was using a 1/8" 2 flute endmill (HSS) taking 1/8" depth passes at 80ipm. I never heard boo from the trim router. At those speeds and depth, my rotary tool would have stalled. I think I could have gone faster. The next time I have a while to just play, I'll crank up the speed and see where the limit is.
- The DW660 came with both 1/8" and 1/4" collets. I have only used the 1/8" so far.
- It's a little nosier than the 1A rotary tool. Really, just a little bit. I'll try to get a readout with my android app to compare. But it's not as high pitched, if that makes any sense?
- Plunging was awesome. Plunging straight down is the worst thing you can do with an endmill. Even a center point endmill. There's a point when the bit bites into the material where there's simply no room for the chips to go, and as such it's tough on the tool and the spindle. Again, the DW660 didn't flinch at plunges.
- Cutting UHMW at higher speeds with deeper passes is better! For one, it's a lot faster. But, regarding 'machining' it appears that the material wants to be done at a higher speed. The chips that came off were slightly bigger, and I didn't see any stringing or melting.
- Weight - slightly more than the rotary tool, but not by much. I should put them on my food scale to compare. (my wife will love that...)
- Size - the DW660 is about 1/2" larger in diameter than the Rotary tool (at their largest points). Regarding workable room, I don't think the extra size shrunk the work envelope by any more than 1/2" in the Y axis.
- Runout - no way of telling really.

I took a picture of the setup on my phone, but using it as a wireless hotspot killed the battery, so we'll have to wait until it charges before I can upload the picture.

All in all, really good stuff. And for $55... I should have made the switch a long time ago.
Shapeoko 1 #0 - a couple of upgrades.
Shapeoko 2 #0 - a couple of upgrades.
Shapeoko 3 #2 - Stock

Tom Smith
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Location: North Vancouver, British Columbia

Re: Rotozip or Laminate Trim Router for the spindle?

Post by Tom Smith » Sat May 05, 2012 6:09 am

edwardrford wrote: - Weight - slightly more than the rotary tool, but not by much. I should put them on my food scale to compare. (my wife will love that...)
This is really exciting news, Edward! A question, though...are you using the smaller nema17 steppers, or the larger (and I assume, more powerful) nema23 steppers? I wonder, despite the similar weights, if the smaller motors would still be sufficient to move this thing around?

The possibility of using 1/4" shank router bits would really open up the possibilities rather than being tied to the 1/8" shank rotary tool bits.
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ShapeOko1 191

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