[diosces]

Hi!
Nice forum, spent the last few hours reading. Seems like a great group of talented people.

I think I'd like to try my hand at a desktop CNC project see if it whets my appetite. We live in a small urban house so size is a major factor I'm into high power rocketry and a small CNC machine that could cut/engrave fins, bulkheads and center rings out of 12" x 15" fiberglass, plywood and carbon fiber stock would be great (mebe some light gage alumin bulkheads as well). Material thickness vary from .125" to 1/2" thickness.

The amount of threads to search here is a bit overwhelming. Could someone guide me towards some build/plan threads that might fit my needs.

Thanks
John

[jalessi]

John,


What is your budget?

Welcome to the Zone,

Jeff...

[diosces]

John,


What is your budget?

Welcome to the Zone,

Jeff...

Thanks Jeff, Im thinking approx $200-250 to start with.

[mlabruyere]

Hi John,

You will be hard pressed to get any CNC, no matter the size, at $250. But if you have access to old printers or copiers they use pretty good steppers. There are inexpensive controllers out there too like Easy-CNC http://www.easy-cnc.com/3axisdriver.html for about $150. There are less expensive alternatives but you'll have to solder the unit together.

The materials will depend on the size, speed, and rigidity you are looking for.

It'll run from discarded gas pipe and skate bearings to linear rails and bearing blocks. Threaded rod and DIY nuts (from plastic) to ball screws. MDF to aluminum structure (extruded 8020 normally).....

So it is possible to do it for that amount but you need to decided what you are looking for and whether or not you have access to "free" stuff....

Matthew

[jalessi]

John,

Do you have access to a CNC router to cut the component parts?

Jeff...

[diosces]

Matt: Thanks for that link. Looks like a controller is a substantial part of the cost

Jeff, I don't have access yet but Im alumni at Steven's Institute of Tech in Hoboken and might be able to get some access to a decent machine to cut some parts

Revised my budget to $350 at this point as i dont want to scratch build a controller.

[ilya]

John,

That's a pretty tight budget you have. I don't think it's possible to build a good CNC machine having 300$. Electronics alone could easily be more than that. And mechanical part is even more expensve.
That is, of course, if you don't want to end up with just a toy that can't reliably cut anything harder than wax.

__________________________________________________ _____________

My DIY CNC machine plans at www.8020CNC.com

[jalessi]

John,

Get a friend with a soldering iron to help you.

You cant beat $64.00 for a 3 axis driver board.

http://www.hobbycnc.com/products/hob...ver-board-kit/

Several Zone members have free easy to follow CNC router plans.

Jeff...

[FandZ]

You should check this one out. You'll still need to add in your electronics but it has everytrhing but the electronics for under 400.

You should probably up your budget. $300 - 400 should be reserved for electronics alone. That's one thing you could reuse on your next machine.

http://modularcnc.flyingcart.com/ind...pid=51&cat_id=

[diosces]

John,

Get a friend with a soldering iron to help you.

You cant beat $64.00 for a 3 axis driver board.

http://www.hobbycnc.com/products/hob...ver-board-kit/

Several Zone members have free easy to follow CNC router plans.

Jeff...

Awesome Jeff.
I've got some past experience as stereo tech so my soldering skills are pretty top notch, the kit is perfect @ $65-prolly about 1 hour to populate and solder, good current output for my purposes, cutting G10 fiberglass sheet.
Just ordered it

I think meshing that driver that with a gussied up variant of Tom McWires's Easy CNC will be good for me.

If I decide to go further I lay off of buying my next level of rocket hardware ($$$$) and upgrade.

Thanks again to everyone for their feedback

[atwooddon]

Like you, I wanted to start with a small CNC to cut parts for my RC model planes. I built Macwire's Easy CNC because it was simple and used components that were easy to find. However, I can not recommend the machine. It will only work for VERY light work due to the nature of the spring loaded bearing approach. I spent a lot more time 'fixing' the design to give it more rigidity than I spent building it originally. However, if you decide to use the basic design, you will have to make it quite a bit larger to accomodate the size parts you listed. In your redesign, get rid of the original bearing linear guide approach and replace it with something much more rigid.

I will also add my vote for the HobbyCNC boards. I built mine in about 2 hours and it worked perfectly. It has been in use for over a year now. You can also pick up inexpensive stepper motors on eBay or electronic surplus stores to get you started.

Don

[draughted]

like they all said. $350 should get you a decent set of electronics
for a fully functioning machine it'll be a grand or over.

i recently finished what i call a capable machine, with gecko g540 drivers, strong aluminium frame custom machined, nema 23 steppers, cheap laminate trimmer spindle, (what i consider the cheapest linear bearing) brass bushings on bright mild steel rail, and chinese ball screws. and all up it was around 1500 to 2000. it only has the
300X300x100 mm work area and i call that a basic machine

[draughted]

not only that but it took a good two years to fully realise the design

[awerby]

Fiberglass and carbon fiber are difficult to cut even with a top-notch machine. The diamond-coated tooling alone will cost more than you've budgeted for your whole CNC rig. And once you've got it working, you'll be making a big toxic mess out of your workspace. Getting these tiny pieces of nasty fibers airborne is a good way to ruin your health. I'd say pay the money to someone else who's set up to cut this stuff safely (probably with an abrasive water-jet machine) and concentrate on flying your rockets instead.

Andrew Werby
www.computersculpture.com

[diosces]

Fiberglass and carbon fiber are difficult to cut even with a top-notch machine. The diamond-coated tooling alone will cost more than you've budgeted for your whole CNC rig. And once you've got it working, you'll be making a big toxic mess out of your workspace. Getting these tiny pieces of nasty fibers airborne is a good way to ruin your health. I'd say pay the money to someone else who's set up to cut this stuff safely (probably with an abrasive water-jet machine) and concentrate on flying your rockets instead.

Andrew Werby
www.computersculpture.com

I appreciate your concern and advice Andrew howewer as a seasoned rocket enthusiast I already cut and shape fiberglass and my carbon fiber layup's with basic handtools and small powertools like dremel & jigsaw, no diamond tip accessories required. I use adequate respiratory and skin protection in a properly ventilated are when doing so.

I'm committed to learning a bit about CNC now and will evolve my budget as necessary, but for right now I'm keeping it to a sub $500 project.


I ordered the HobbyCNC PRO Chopper Driver Board Kit last night.

Salvaged a 15 amp +/- 24 VDC switching supply from a previous hobby project (hybrid stereo pre amp)

I have several ebay bids on some low cost, decent torque Vexta steppers
Also gutted several old printers with some Applied M steppers

For bed and structural components I've got some spare 1515 rail (we use for rocket launch rail), and 3/4" MDF.
Gotta pick up some 3/8" or 1/2" thick plexi as well as some of the other aluminum framing
Mcmaster has some decent rails, I like these Plain PTFE bearing & block with rail, static load rating is more than sufficient for my needs. A little dumpster diving yielded some nice industrial strength drawer rails that work for X/Y axis

[draughted]

good to hear!
i don't know what you have in mind but you should look at the layout of machine that best suits your needs. you are looking at a diy so the option are endless but you'll probably end up with a fixed or flying gantry.

go the mcmaster rail if you can afford it. it will be in valuable for any machine.
but your design will have to be rigid and inflexible.

[FandZ]

You should check these guys out. http://www.automation-overstock.com/...ies.asp?cat=71

[draughted]

thats pretty good but the chinese ebay store 'linearmotionbearings2008'
sell rail even cheaper.

you should also look at ballscrews for speed and accuracy.

[FandZ]

thats pretty good but the chinese ebay store 'linearmotionbearings2008'
sell rail even cheaper.

you should also look at ballscrews for speed and accuracy.

Is the before or after shipping? They do have some good stuff but sometimes shipping can be high enough to make it not that good of a deal.

[draughted]

well they were cheap for me. i live in australia so asian shipping is cheap.
and these guys always avoided the chinese export tax by miss representing the item as a cheaper one.