Total beginner questions
December 6, 2012 at 2:41 am #2477
Where is a good place to post total beginner questions?December 6, 2012 at 4:03 am #4217December 6, 2012 at 6:38 am #4218
Cool. So, my first question is a basic usability question. Currently, I have a little side project where I do some wooden cutouts for a preschool teacher, who uses them as little themed projects for her class. Like a tree and a star for Christmas, a turkey for Thanksgiving, a tulip for spring, etc. (the back story is that her father used to do it for her, then he died, her husband took over, then he died, and now I am doing it for her) For these, I simply trace the patterns on thin plywood (15-20 at a time) and then cut them out on my scroll saw.
Would a CNC like this, equipped with a dremmel-type tool and a roto-zip type blade (I have the rotary tool) be able to cut out the little shapes for me? How would that work – cutting out shapes from thin plywood? Wouldn’t the blade go through and start cutting into the base? Or do you put down an extra sheet of plywood that does get cut up a little and you replace it periodically? I have seen videos of a rotary tool being used as an engraver, but not for cutting out plywood shapes. Is this the wrong tool for doing what I already do with the scroll saw?
I enjoy doing woodworking with the scroll saw, but I thought it would be more consistent and faster to do these on a CNC machine – well at least more consistent and taking less of my personal attention. Then I might be able to do a few more projects like this without getting burned out at the scrollsaw for hours and hours at a time.December 6, 2012 at 11:27 pm #4219
@CRODGERS – yes you could pretty easily cut shapes like this with a CNC.
Roto-zip blades would work, you can also get carbide end mills from places like McMaster-Carr or Onsrud that are specifically for this type of cutting.
You would use a spoiler board underneath to protect the base. Our design makes it pretty easy to replace the base even if you totally trashed it. You’d also need to secure the piece you’re cutting out to keep the xmas tree or other shape from moving after it is cut –either with double-sided tape or a few tabs connected to the rest of the stock would work.
You could certainly get more consistent results with a CNC, but depending on your volume it might not end up saving you work (although cutting on a CNC is definitely cooler than a scroll saw, imo). Another option would be to make one template for each shape and cut them with a trim router, using the template as a guide. This would improve consistency too.December 7, 2012 at 3:45 am #4220
Thanks! I was wondering how you would get the pieces to not fly out or get fauled up when you do cutouts… double-side tape – smart!
So if I have a project to do where I can put, say 3 trees on a sheet, so I need to cut 7 sheets, it seems like that would be a case where I could use a spoiler board that is reused for all 7 sheets and then stored to be reused the next year… it will already have grooves where the blade cuts through… I saw a video on resurfacing a spoiler board, so I figured out what that is…
So many different designs… where whould I find info on pros and cons for different designs? For example -
* belts/chains versus threaded pipe/screws for movement?
* Tubes and cutout holes versus rails and bearings for the rails?
* uchannel rails versus angle pipe pointing up?
* <100 oz/in stepper motors versus 425oz/in stepper motors?
* move the tool (x+y+z) around the object versus moving the object (x+y) around the tool (z) (I think one is called gantry? or is that something else?)
Size… I suppose most parts are reusable… so if I start out with a small CNC with a cutting area of only like a foot by a foot and a half, I could eventually upgrade by building a larger frame. I would think my main considerations are things like * do I need new/longer rails? * are my stepper motors strong enough to move a larger system in all directions, etc. As long as they are strong enough, I should be able to reuse the stepper motors, electronics, software and cutting tool, right?December 9, 2012 at 4:22 pm #4221
Our philosophy is an offshoot of value engineering, where the success of a design is assessed across a matrix of factors. Many folks in the CNC community seek accuracy at all costs (and boy, do we mean costs). We feel that this project strikes a good balance between cost and precision (see cut examples here). We’ve also got really thorough documentation and a design that’s meant to be hacked/shared. It sounds like you’ve got the right idea – try out a small kit, then upgrade at a later point once you know more about the field. If that’s the tack you take, I wouldn’t worry to much about which kit you pick, as long as others have reported success with it.December 9, 2012 at 9:31 pm #4222
@CRODGERS, sounds like you’ve got a pretty good handle on the range of options. Very broadly, the choices will depend on budget and whether you want a high-precision machine or one that can churn out lots of parts (or both). Here’s a napkin-drawing version of how these options look:
belts chains acme rod ball screw rod
bushings skate bearings precision bearings
angle rail linear bearing rail precision rail
For the specific project you mention, the difference between belts/chains/threaded rod will probably not be important – your requirement is quantities of oddly-shaped parts with relatively loose tolerances (assuming you don’t need your xmas trees accurate to .001″).
You are right that core parts of the system (motors & electronics) are re-usable in different mechanical setups. With our design, the motors/controller are the biggest expense, so once you have that you would have ability to play with different bearings, etc.
The difference between <100 oz/in stepper motors versus 425oz/in is pretty big. Probably something around 150-200 is more than enough, though is also depends on if/how gearing is set up.December 25, 2012 at 4:40 pm #4225
Hello all my name is shavoree,I’am working on a diydtg direct to garment printer and I came across a vidof some one using an x,y,z axis table and I wanted to know if any one here has kowledge about the parts that he is using.http://youtu.be/y03q5jldUHgDecember 27, 2012 at 4:59 pm #4226
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