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Dremel upgrade - Rotozip, wood carver.....Air Turbine?

Discussion in 'Original Phlatprinter MODIFICATIONS' started by firetrappe, Oct 7, 2009.

  1. firetrappe

    firetrappe Member

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    The motor on my Dremel (not the one in the Phlatprinter) died a couple of days ago, so rather than buying another one I'm thinking of upgrading the one in my Phlatprinter to something a bit more powerful to enable me to cut harder materials.

    My first thought was to buy a Rotozip with a flex shaft as others have done this mod, but having looked into it, it appears that only the RZ3 and RZ5 models are available in Europe. Neither of which are variable speed and the FS2 flex-shaft isn't available over here either :( .

    Having done quite a bit of searching, the next alternative i've found is a Wood Carver, this is basically a motor with a flex-shaft drive and a choice of collet or chucks that can be fitted to the end of the shaft. Wood Carver/Drive Unit : http://www.axminster.co.uk/src/froogle/ ... -20091.htm Collets/Chucks : http://www.axminster.co.uk/src/froogle/ ... -30234.htm
    I believe Kwok found a similar unit at HarborFreight :http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=40432
    It appears that these units are more powerful than a Dremel but still not on par with the Rotozip.

    Now onto the Air Turbine. I don't think this is an option for me at the moment, but I thought it was pretty cool and worth sharing.
    I found a guy in the UK who is converting small mill's to CNC : http://www.compucutters.co.uk/machines/ ... ctMore.htm
    If you have a look at this page and scroll down to 'High Speed Spindles', you'll see he's made his own Air Turbine spindle. The spindle is driven by a household vacuum cleaner and extracts dust as it cuts! There's not much info about it, but there are some photos i've found here : http://www.compucutters.co.uk/gallery/i ... e_full.JPG
    http://www.compucutters.co.uk/gallery/m ... irbine.htm
    http://www.compucutters.co.uk/gallery/m ... irbine.htm

    The 'Airbine' is available to buy for £150, but looks too large to fit in a MK1. I think it's a cool concept though!

    If any of you have any advice or opinions on which of these options would be the best upgrade path for my Mk1 then i'd appreciate it.

    Cheers,
    Si.
     
  2. kram242

    kram242 Administrator Staff Member

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    Very cool Si!
    I love the concept, and the fact that its inexpensive to make. If I were in your position I would first take the dremel apart to study how it was built and to see if the plastic casing could be cut down to add this type of set up. Really if you think about it you may just be able to get a couple lock collars that fit over the chuck of the dremel and sandwiches the turbine in place then it would be a matter of a tube of some sorts to surround the turbine. I think with a little patience and enginuity it could be done on the cheap.
    Another way you could do it without the turbine is a way I once tired with and over head gantry style machine that was very dusty. I took an old plastic soda bottle with just the top cut down a bit and fit it over the bit and on to the little lid that screws on to the dremel plastic housing. I glued that in place and that created a foam catching funnel. I then mounted a small clear hose at an angle to create a vortex of air inside the funnel and sucked the foam in as it came around. That worked out really well.
    Here is a pic to better show what I am trying to explain though text. :)

    [​IMG] Attached files [​IMG]
     
  3. kyyu

    kyyu Active Member

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  4. tvcasualty

    tvcasualty New Member

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    If we knew someone with a hard core CNC setup maybe they could make a collet adaptors for brushless motors? :D
     
  5. kyyu

    kyyu Active Member

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    Lots of interesting things on that compucutters website. Anyways, he mentioned there is a magazine article where you can get more info on the air turbine. I tracked it to this issue:

    Model Engineers Workshop magazine
    Issue 103, Year: 2004/5, Month: December/January
    Page 42
    author: Bartlett
    article title: "DIY Air-Turbines for PCB's Engraving and Internal Grinding etc"

    You can buy back issues here:
    http://www.myhobbystore.com/2969/Magazi ... ssues.html

    -Kwok
     
  6. firetrappe

    firetrappe Member

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    Thanks for the feedback guys :)

    Mark, good idea stripping my broken Dremel down and seeing what's inside, i'm sure the collet and shaft will be easy to remove. I don't really have the time or equipment to fabricate a metal turbine impeller at the moment, but I'm sure it's worth investigating further in the future. As well as the built in dust extraction advantage, the airflow over the cutting bit should keep it nice and cool. Also as it's air driven, it overcomes the problem of different countries having different mains voltages (110V, 240V etc).
    I like your soda bottle mod, ingenious :cool: Thanks for the illustration too, that would have taken me longer to draw than to do the actual mod! lol . That's another idea for me to think about.

    Kwok, I spoke to Fozzy about the rotary tool he is using early on during his build. Unfortunately the unit he's using has now been discontinued, I believe he bought it a few years ago. Those die grinders look pretty cool, i'm sure it would be easy enough to regulate the air pressure/RPM of the tool, but I think it would take a decent sized compressor with an air tank to power one.
    BTW, nice work finding more info on the MEW article. I did a few searches for it last night, but couldn't find anything.

    Erik, I've thought a number of times about using a brushless rc motor with an esc as a spindle. Like you say, the collet adaptor is one issue, the other is whether the bearings in the motor would withstand the loads we'd be putting on them?

    Si.
     
  7. kyyu

    kyyu Active Member

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    I say, don't jump into trying to use brushless rc motors, unless you are willing to spend alot of time and money experimenting. I bought a whole bunch of stuff, thinking it would be easy to do, but gave up. Got some servo testers, some speed controllers, and small high kv motors. I even figured out how to short the pot in the servo tester, so you can just flip a switch for arming the esc; and then flip it again and you would be at your exact set rpm. Let's face it rc electronics is not quality stuff and I think asking it to run continuously is asking it to do too much. This is not even getting into the adapter and bearings. The motors got really hot, after as little as a 15 seconds, so I could not hold on to them any more. I was testing them with a pc power supply (12 volts) and would start stuttering after half throttle. So either it reached the 10 amp limit of the power supply and was cutting of or reaching the pulse limit of the esc. This was under no load. Could you imagine running 10++ amps continuously in so tiny a motor. One was a 3k kv blue wonder and the other was something like a 4.5k kv inrunner. I also, tried to make a adapter and wasn't successful there either. Found a flex shaft coupler for a rc boat that fit the shaft of one of my motors and I just had to drill out the other end. But there was vibration when it spun.

    That being said, I have seen pictures of a cnc mill using a large rc brushless outrunner.

    -Kwok
     
  8. kyyu

    kyyu Active Member

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    Hey Si, if you get more info on the air turbine, I would be interested. :)
     
  9. firetrappe

    firetrappe Member

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    Kwok, I didn't know you'd tested using rc motors for a spindle, that's really interesting, thanks for posting the info.
    I did a bit of searching today for 'DIY CNC Spindles' and found some details on another UK forum about a guy who's been experimenting using motors from HobbyCity. The thread makes for some interesting reading : http://www.mycncuk.com/forums/showthread.php?t=445

    [​IMG]
     
  10. kyyu

    kyyu Active Member

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    Thanks for the link. Yea, I waste my time and money on alot of strange ideas. :cool: I probably shouldn't mention this, but here goes. ;) Toyed around with the idea of an ultrsonic cutter. Even bought two different cheapy untrasonic stain cleaners to test out. But I just don't have the equipment or knowledge to go much farther. But imagine a needle which cuts foam, but makes almost no noise. :shock: Here are some example on youtube that got me interested. These are food demos, but there are demos of cutting cd cases and even carbon fiber.
     
  11. firetrappe

    firetrappe Member

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    Kwok, those are cool videos! I hadn't thought of ultrasonics. I remember seeing a Youtube video of a guy cutting foam using a reciprocating needle attached to a CNC machine which was pretty cool. I've got a little ultrasonic cleaning tank that I use to clean my airbrushes, but that's about all the experience i've got with them.

    I ordered a copy of the magazine with the Air Turbine article in yesterday, but unfortunatly I received an email from them today saying that they don't have any copies left :( . Apparently if you subscribe to the magazine then you can view back-issues online, but I don't really want to pay for a subscription just to read a 4 page article. I may email the author and see if I can get some more info.

    BTW, I found out today that Dremel have released a new tool in Europe with a Flex-shaft. It looks pretty cool, but costs over $230 :shock: : http://www.dremeleurope.com/dremelocs-u ... rod_id=397
     
  12. FozzyTheBear

    FozzyTheBear Member

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    Si, for the cost of those, the Axminster and that new Dremel are not worth the money.... They're a little more powerful than the standard Dremel but not much.

    If you want to spend about £130 then you'd be better off getting a genuine Rotozip. They're available for about that and if I remember correctly they'll give you about 500W. Rotozip have got a list of local dealers on their UK web site.

    Best Regards,
    Julian (Fozzy The Bear)
     
  13. firetrappe

    firetrappe Member

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    Foz, thanks for the input, i've been thinking the same about the Axminster and the new Dremel. I just can't see the Axminster cutting it (sorry) as i've read that the flex drive gets hot quickly and needs lubricating daily. I'd have already ordered a Rotozip except that the flex-shaft isn't available in Europe and there aren't any variable speed versions here either unlike in the US :roll: . I'm looking into whether it's possible to make the speeds of the UK versions adjustable or whether i'm better off buying one of the US versions and an inverter capable of converting 240V to 120V.

    I've looked everywhere I can think of for a spiral saw similar to the one you're using (thanks for the info BTW) but no-one seems to sell anything like it over here anymore.

    Oh yeah, before I forget, I did find something pretty cool while I was searching the web.... Check out the dust extraction kit on this page : http://hooftrimmingtools.net/mcart/inde ... e=3&cat=14

    Si.
     
  14. TigerPilot

    TigerPilot Well-Known Member

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    firetrappe, don't use an inverter, use a transformer. They are ease to get or to make yourself.
     
  15. FozzyTheBear

    FozzyTheBear Member

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    Absolutely!! They are easy to get from most builders merchants.... because on site outdoor power tools have to be run at 110V in the UK (health and safety regulations). So most builders have them. You can usually pick up a site transformer second hand... they come as a blue or yellow box with a handle on top... an input for 220V to 240V and a C-Form connector output that carries 110V.

    The downside is that they're not cheap! In fact far from cheap.... Unless you know somebody who has one that has accidentally fallen off the back of a lorry :lol: ;)

    Unless you're an electrician, and know exactly what you're doing, then I wouldn't recommend building your own either.

    Best Regards,
    Julian (Fozzy The Bear)
     
  16. firetrappe

    firetrappe Member

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    Yoram, you're correct, I meant transformer :oops: .

    My latest idea is to buy a single speed Rotozip from the UK and use a speed controller to slow the rpm down. I've found some controller modules which aren't too expensive : http://www.quasarelectronics.com/motor- ... rivers.htm . I'm just trying to figure out whether any of them will allow me to control the rpm via Mach rather than having a basic potentiometer. If anyone has any ideas then i'd appreciate some input.

    Si.
     
  17. gasmasher

    gasmasher New Member

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    One idea if you have another axis on your control board is to hook a small stepper to the pot and then use gcodes for the A axis.
     
  18. kyyu

    kyyu Active Member

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    How about the info here: http://www.cncathome.com/vfd.html
    He's doing something different and messing with the steppers, but the part about the spindle looks like what you want. My read on it is, Mach 3 can output 0-5V PWM (pulses) and you need a small circuit to convert it to 0-10V regular analog voltage?

    -Kwok
     
  19. FozzyTheBear

    FozzyTheBear Member

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    That's pretty cool stuff Kwok....... I like that milling machine control, especially as he's controlling a 3phase motor.

    Best Regards,
    Julian (Fozzy The Bear)
     
  20. kram242

    kram242 Administrator Staff Member

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    Very cool, did you guys see that he used a digital caliber for his z axis read out!
    Thanks for the link Kwok
    Mark
     
  21. firetrappe

    firetrappe Member

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    Hey guys, thanks for all the responses :)

    Kwok, thanks for the link, that's pretty cool stuff. I think you've hit the nail on the head with the additional circuit required for Mach control. The company that I bought my steppers from does a speed control board and also gives details of how to set it up with Mach : http://www.rhonmac-cnc.co.uk/speed_cont ... _sheet.htm

    I'm suprised that no-one appears to have tried controlling the spindle speed for their Phlatprinter yet (unless they have and i've missed it).

    edit : A bit more searching and I found this thread from Eric (dbtoutfit) : http://www.cnczone.com/forums/showthread.php?t=30070
    I thought post #13 was partiularly interesting.

    Mark, I hadn't noticed that digital caliper...now that's a cool idea! I wonder if the same idea would work on the Phlatty if we could remove the LCD display from the caliper and extend the wiring so it could be mounted outside the machine? :geek:

    Si.
     
  22. FozzyTheBear

    FozzyTheBear Member

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    Great idea, but very tricky to impliment.... they're built as a single chip board with the sensors and the LCD all in one unit.

    But there are some very cheap DRO units out there that might be adaptable! I'm on the case now!! :D :ugeek:

    Best Regards,
    Julian (Fozzy The Bear)
     
  23. kyyu

    kyyu Active Member

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    I didn't notice the digital caliper, either. Another interesting fact, is some of the digital calipers have a build in serial interface. You can use it to, output the data to your electronics or computer. The one I have, from Harbor Freight, has it. There is a picture (at the very bottom) of what it looks like. It's hard to see where he hacked it up for the connector, but originally there is a door there just like the battery door: http://www.compendiumarcana.com/caliper

    -Kwok
     
  24. firetrappe

    firetrappe Member

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    Kwok, would you believe it, i've got one of those digital calipers here and I never even realised that it had a data port! Now things are looking more viable :D . I haven't a clue where I can get a data cable for it from, but I did find this link that has details of changing the button cell for a capacitor and powering it from the data cable : http://www.robotroom.com/CaliperCapacitor.html

    Fozzy, the calipers are available from Maplin Electronics for £10 ;)

    Still looking at flexshafts and drive unit options, I came across the 'CarveWright' machine sold in the US. I'd never heard of it before, but it's like an expensive Phlatprinter that's less versatile. It does have some pretty cool features though, including the motor and spindle.



    Si.
     
  25. FozzyTheBear

    FozzyTheBear Member

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    I think I paid about £300 for my Mitotoyo ones........ :roll: and they haven't even got a data port on them DOH!!!!

    £10 looks like a bargain deal if we can get them to spit out the data and manage to translate it into something useful.

    That carvewright machine is spectacular.... especially like the way it self sets it's bits and measures the workpiece. Given the hard material and deep cuts it can do I'd say the price on that machine is pretty damned good really. That said I think my phlatprinter is quite capable of those sort of cuts. Still working one step at a time towards getting it to do them.

    Best Regards,
    Julian (Fozzy The Bear)
     

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