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Rascal CNC

SP0NZ

FT CAD Gremlin
Mentor
#1
Rascal CNC Logo.png
RASCAL CNC
CUT IT - BUILD IT - FLY IT



The Team:
Nic Lechner (nerdnic)​
Todd Optional (Litke) ()​
Kevin Matusik (blackkrystal73)​
Dan Sponholz (SP0NZ)​


The Goal:

Deliver free plans and instructions to build a DIY hobby-grade CNC machine focused on the model airplane community.​

Wood Parts v1.0_sm.jpg

Dedication:

The Rascal CNC is dedicated to Michael "Crash" Hancock. He was in my eyes, the father of CNC for the RC community. Without The Crash Cast and his efforts, a lot of us would have never considered getting into CNC, not to mention building a DIY CNC machine. If by some miracle you can read this from the great air field in the sky... well played my friend, well played! Rest in peace Crash, you will always be my friend and hero.
It is in Crash's honor that we give you the Rascal CNC design, in the most sincere form of love for the community.
-Kevin



The Specs:

Foot Print

42.0 in X 42.0 in (1067 mm X 1067 mm)

Cut Area

30.5 in X 30.5 in ( 775 mm X 775 mm)

Cost (approximate)

$475.00 US

Construction

3/4 in cabinet grade birch plywood

 

Aluminum extruded rails

 

RM2-2RS steel V-bearings

Drive System

Y-Axis: 2X NEMA 23 (178 oz) stepper motors

 

X-Axis: 1X NEMA 23 (178 oz) stpepper motor

 

Z-Axis: 1X NEMA 17 ( 84 oz) stepper motor

 

GT2 belts and sprockets

 

Arduino CNC Shield USB

 

Arduino UNO, 4-DVR8825 high current stepper drivers, 1/32 stepping

Spindle

Engraving 0.4KW Spindle Motor ER11 with PWM controller

  



The Release Date:
November 1, 2017 (tentative, if we don't hit it we will give you a full refund ;))​


Please be patient as we start to add more information for you to help you decide if this is a project for you. Ask questions and we will do our best to answer them and update information here. Thanks for your patience and support.


Social Media Links:
 
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SP0NZ

FT CAD Gremlin
Mentor
#2
Link --> Rascal CNC Parts List

DISCLAIMER: The shortcut above is a link to a live Google Sheet document and is subject to change at any time and without notice. We fully expect the community to help us find alternative sources for components to help keep the Rascal both affordable and relevant. We will do our best to keep you informed when updates to the parts list occur.


Link --> Rascal CNC Wood Parts (Short Kit)

The zip file contains a DXF file of all the wood parts required for the Rascal short kit. These files were designed for 3/4" furniture grade plywood. They are supplied for you to be able to cut your own parts should you choose to do so.

Wood Parts v1.0_sm.jpg

RCNC Wood Parts.png


Thanks,

- Kevin, Todd, Nic, and Dan
 
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SP0NZ

FT CAD Gremlin
Mentor
#3
Build videos/instructions place holder


Flite Test Community Cast
The Rascal team would like to thank Mike Finley and Patrick Murphy for having us on the podcast to talk about this project.

035-Rascal DIY CNC with Kevin Matusik and Todd Litke
 
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earthsciteach

Moderator
Moderator
#6
I am wrapping up a major organization of my workspace so I can accommodate a Rascal! Thank you, Kevin, Todd and Dan for being on our podcast! I am really excited for this!
 

nerdnic

nerdnic.com
Mentor
#7
I'm bummed I missed the podcast, was tied up with life stuff. It's great seeing all the community excitement around the Rascal. We can't wait to release it and see what you guys do with it!
 

JimCR120

Got Lobstah?
Site Moderator
#11
Pardon my ignorance, but if CNC and 3D printers are both fabrication machines, what would keep from building an all-in-one that maybe just needs interchangeable print/machining heads? I'm very intested in this but would like to keep cost, space, and spousal frowns down to a minimum.
 

jhitesma

Some guy in the desert
Mentor
#12
Pardon my ignorance, but if CNC and 3D printers are both fabrication machines, what would keep from building an all-in-one that maybe just needs interchangeable print/machining heads? I'm very intested in this but would like to keep cost, space, and spousal frowns down to a minimum.
Nothing. A 3D printer is just a small CNC machine with an extruder attached. The big limit is software and to a lesser extent the electrical hardware (most of the controllers used on traditional CNC machines don't have an extra output that can be used for an extruder.) Also the way they're controlled tends to be a little different. Most CNC machines have a "Dumb" controller that does little more than translate one type of pulse into another to control the stepper motors - 3D printers on the other hand tend to process the gcode on their controller itself...but you can build a CNC that does that as well.

Here's a video from someone who put a 3D printing extruder on their CNC mill:

The MPCNC that a number of us have built is an interesting hybrid setup. It's built from 3D printed parts and conduit (to keep the costs very low) and it uses the same RAMPS or Rambo controllers that are the most popular used for 3D printers. It's also designed with a toolmount that makes it easy to switch tools with just a few screws - though some of us have switched to a quick change tool mount that allows even easier tool changes (and for low stress tools like pens, vinyl drag knife, 3D extruder, and lasers it can even be tool free.) On my machine I have a variety of tools I use depending on what I want to do:
  • Router (as a spindle for cutting wood/plastic/soft metals)
  • Needle cutter (for cutting DTFB and WR foam - way better than a spindle IMHO)
  • Pen holder (for large drawings)
  • 2.8w laser (cutting posterboard and balsa as well as thin ply, and engraving wood and etching on anodized aluminum)
  • Drag knife (small one designed for cutting vinyl - nice for making decals!)
  • 3D printhead (I made one but actually haven't used it on the CNC yet.)

I also have a mount for my dremel which I used before I had a router - but dremels are really underpowered and running them on a CNC is a great way to burn them out (I speak from experience here!)

I want to say I may one one or two other toolheads but can't think of them right now...might just be thinking of the various needle cutter designs I've gone through improving it and various router mounts I've used. There are also people who've made paste extruders for things like clay or even pancake batter.

On the rascal it might be a little trickier to use it as a 3D printer. You'd have tons of X/Y space but might be slightly limited on due to the gantry design...still plenty to work with but might not have as much Z as a traditional 3D printer. The bigger issue would be the GRBL interface which doesn't have an extra stepper controller for an extruder. One easy way around this would be to use a RAMPS or RAMBO board instead - it wouldn't be that hard to do but probably isn't something the design team is willing to help with since their hands are pretty full already just with what they're doing. This other nice thing about using a RAMPS or RAMBO instead of GRBL is you can run untethered and just load your gcode to a SD card and let the machine do it's thing without having to be tied to a dedicated computer. On the other hand you have to work a little differently than a traditional CNC machine with that kind of setup - it's hard to explain how it's different though unless you have experience with both setups.
 

JimCR120

Got Lobstah?
Site Moderator
#13
Thanks for the info (Jason, is it?)

Your responses are consistently thorough and helpful.

Regarding my question, what are your thoughts about the value of an all-in-one CNC/printer? For the non-professional hobbiest would an all-in-one do an adequate job for a reasonable cost& effort in your opinion? Of all the places to start, where/with what would you recommend?
—Jim
 
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jhitesma

Some guy in the desert
Mentor
#14
Thanks for the iinfo (Jason, is it?)

Your responses are consistently thorough and helpful.
Jason it is, and thanks :D

Regarding my question, what are your thoughts about the value of an all-in-one CNC/printer? For the non-professional hobbiest would an all-in-one do an adequate job for a reasonable cost& effort in your opinion? Of all the places to start, where/with what would you recommend?
—Jim
My feeling towards an all in one is...it's ok but not ideal. 3D printers are SLOW. That's their biggest issue IMHO, it takes hours to make a single part. A local friend is building an openBuilds Sphinx CNC: http://openbuilds.org/builds/c-beam-sphinx.3605/ he asked me if I could print the plates for him with my 3D printer since he saw some people had used 3d printed plates to get it up and running. Well...I could. But...the smallest plate was looking like a 2 hour+ print and there are 8 plates. I was able to cut all of the plates in less than an hour on my CNC. I only cut them from MDF - but they're probably still stronger than 3D printed would have been and should be good enough to get him and and going enough to use the machine to cut new plates for itself.

A CNC as a 3D printer is generally probably going to be slower than an already slow 3D printer. CNC's have heavier parts and that means slower accelerations. Most CNC's are capable of faster movement speeds than would be practical for 3D printing - but with 3D printing there's a lot of starting/stopping so acceleration plays a larger roll than it usually does with milling.

So...along those lines while I have an extruder setup to mount on my CNC I haven't because I don't want to tie the machine up for hours on end doing prints. I mostly have it so I can do prints that won't fit on my printer (like the neck of the Hovalin I'm working on for my wife.)

That said there are quite a few people who built MPCNC's with parts they purchased and then use them as 3D printers more than they use them as CNC's. It's a matter of your needs really.

Personally I'd say if you have room and budget for both then it's best to get both. Of course that's not always the case. And if you have to compromise it's far better to use a CNC as a 3D printer than to try and use a 3D printer as a CNC (printers are much less rigid and smaller.) But adapting most CNC machines to work as 3D printers isn't straight forward and would take a good bit of knowledge about controllers/gcode to get working well.

If you really want an all in one then the MPCNC is a good option since there are quite a few people doing that with it already. The Rascal would also be a good platform for it - but you'd be on your own for controlling an extruder. If I was to try and turn a Rascal into an all in one I'd probably ditch the GRBL board and go with a RAMPS or RAMBO - you'd give up some ease of use for milling but you'd have a much easier time using it as a printer.

But...what I would do is build one machine and then use it to build the other. In fact...that's what I did :D I built a 3D printer from a kit (Just under $300 when I did it almost 2 years ago) and then used it to print the parts to build my MPCNC. I use the snot out of my 3D printer...I use the CNC a lot too...but since it's messier, noisier, and stock tends to cost more than filament I don't use it quite as much as the 3D printer.

You could also go the other way. Build a CNC like the Rascal and use it to cut and print parts (or find someone to print parts for you) for a 3D printer.

So...personally I wouldn't want to give up either of my machines or try to make one of them do both jobs. If I absolutely had to though I'd go with just the CNC and set it up for printing. But doing that with a CNC other than the MPCNC would take more work than the MPCNC due to the MPCNC using electronics that are more derived from the 3D printing world than the traditional CNC world.
 
#16
Hi guys I remember from the Podcast that you just up graded from NEMA 17 to 23 for the gantry but you list GT2 belt trying to get familiar with the parts I have been on the open build site looking and they said the GT3 was recommend for the NEMA 23 just asking:).
 

JimCR120

Got Lobstah?
Site Moderator
#17
excited to start building my own CNC Rascal!!!
Rafi! Cześć! So glad to see you post! If you're planning to be at FFE'18 I plan on bringing more pie.

Thanks again Jason for the pros and cons. I appreciate the peace of mind in making informed decisions. If you were to start over again building a 3D printer and then printing parts for the CNC, which 3D kit (or unit) would you choose/recommend?
 

jhitesma

Some guy in the desert
Mentor
#18
Thanks again Jason for the pros and cons. I appreciate the peace of mind in making informed decisions. If you were to start over again building a 3D printer and then printing parts for the CNC, which 3D kit (or unit) would you choose/recommend?
If budget wasn't a factor - Official Prusa i3 hands down. The new Mk3 is mind blowing and it's the printer that almost all of the cheap clones are based off of. But it's also almost three times what I spent on my printer. You do seem to get what you pay for though and I've yet to see anyone regret buying one.

Best bang for the buck...I'm really not sure. I love my Folgertech 2020 i3 - but it's definitely not for everyone. It's a "kit" but really more of a "box of parts that can be assembled into a 3D printer" than what I would consider a well thought out kit. The instructions are not great and in some ways flat out wrong about how to assemble it. But it has a large community of users and Folger is good about replacing damaged/missing/non-functional components (which unfortunately are common.) At the time I bought it I was pretty sure it was the best deal out there (I've been interested in building a 3D printer and CNC for over 10 years and started collecting parts to build either several times but never had the funds to make it happen and until recently didn't feel 3D printing was capable of quality worthy of the cost.)

But...there are a lot of new options like the monoprice, Anet, CR-10, and "clones" like the one FT sells. I haven't really kept up with the latest best bang for the buck printers now that I have one. If I was to make another printer I'd probably do something like the i3 variant the designer of the MPCNC came up with: https://www.vicious1.com/projects/project-3d-printer/ in fact I almost started building one just for the fun of building it...but I really don't have room for another and doubt I could sell it for what it would cost to build. I don't really see myself buying another 3D printer any time soon since mine does what I need and my budget is tight. But I would like one with multi-material support - so at some point I'll either upgrade my existing printer or build another. I doubt I'd buy one since for me building is a large part of the fun ;)

If I had the room I would be seriously considering building a rascal when they release the design. In fact I'm kind of hoping someone local wants to build one and asks me to cut the plates for me just to see how it goes together. It looks like a very nice design that would probably be more rigid than my current MPCNC...but it would be cheaper to upgrade my MPCNC with the new improved parts and shorten it's legs a few inches (I have way more Z than I need or use) and then I'm not sure there would be a big stiffness difference.

More likely what I'll end up doing is finishing the low-rider I started and use that for big things like DTFB. And re-build my MPCNC as a smaller machine with the new parts so it's much stiffer. I like the low rider for big stuff since it takes up so much less space. I can barely fit the 48" square table I build for my MPCNC in my little 10'x12' shop and having a big CNC machine filling 90% of it is a bit of a bummer. With the low rider I could just push it to the side when I'm not actively using it and have the table available as a workbench - which would be a BIG bonus in my cramped workarea!
 
#19
Hi guys I remember from the Podcast that you just up graded from NEMA 17 to 23 for the gantry but you list GT2 belt trying to get familiar with the parts I have been on the open build site looking and they said the GT3 was recommend for the NEMA 23 just asking:).
6mm GT2 belt is plenty strong enough for our needs, but I have found steel reinforced GT2 that I will be recommending for the Rascal build. just in case you want to cut more than foam...lol

http://www.ebay.com/itm/2M-x-6mm-Open-End-Steel-Cords-Reinforced-PU-GT2-Timing-Belt-for-DIY-3D-Printer-/131769331276?epid=917888420&hash=item1eae106e4c:g:abwAAOSwDNdV4BM4

Rascal will need at least 4- 4.5 meters of belt. This link is just a quick example. I have found a cheaper source. Hold out for the official parts list.. all the links and current prices will be listed.

Kevin
 
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