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View Full Version : NEW MEMBER: about to build my first CNC machine



CHIpHload
15-03-2016, 08:37 PM
well , i gotta first thank all these peoples who build a wealth of information for people like me trying to get understanding in cnc, been reading for a few weeks now i feel committed to nut housing :joker:, must admit , a few years ago now i first seen cnc & diy builds i did think oh thats a bit gimmicky , alas as i have grown my understanding i think that may have been an impulse reaction to the fear & intimidation of building or beginning to comprehend such a task. i obviously now see the value of being able to complete a task as efficiently as numerically possible. i would like to build a machine but really like to avoid waste , aiming to build my optimum machine right first time(is it possible???) sure then it immediately starts looking like there's about 3 machine i should build.

initially im thinking birch(russian)plywood torsion box bed & gantry, have seen some designs suggesting optimized for attenuation of resonance while retaining high stiffness/rigidity-speed/agility balance . this part may change , although weight being a consideration is why currently lean toward plywood build. again early doors so may change spec here.

i would very much appreciate more experienced advice and views on ANYTHING you see that may need better consideration

so to the nitty gritty, my aim is around X1220mm x Y610-814mm x Z<150mm travel , maybe with main base having 1 or 2 additional beds, looking at http://www.axminster.co.uk/axminster-200mm-rotary-table-211556 how difficult could it be to also incorporate such a thing to make twists , text around items, work on four faces of an item?? don't want to bite off more than i can chew though,as this part would need be removable may be complicated to do if at all, and not sure i know

simplicity suggested 2 motors direct drive 2 2010 fixed-fixed ballscrews on either side X, but pulleys & belts with 1 motor for X may be the way to go for me,offering more options and some isolation/attenuation. if i am correct 1401-1460mm depending on which length ballnut should give me 1220mm travel but what about pulleys , do pulleys require longer screw or if i am ordering fixed-fixed will there be room for pulleys.

maybe my discombobulated ramble should have a synopsis....... mostly wood work machine , never machined aluminium and probably not feasible in current thought process though would be a beautiful thing to do ,as i said ply build with damping and isolation?? although then juggling should i buy in machined plate and build small machine ,hwin rails etc capable of alu work then build , woodworking machine Z & parts of Y from plate ,woodworking machine capable of cutting sheet , twisted legs etc , clamping on side of bed for dovetails , mortice & tenons. sbr20 on X,Y & Z ? ,two 2010 ballscrew on X, 1610 on Y, 1605 on Z.beneficial or detrimental 2010 2005 screws Y & Z , well the synopsis is just turning me more unresolved problems:eagerness:

anyhow,would be great if i could get recommendations for CAD software, i can start making some tangible design,then will have a drawing i can submit to the GOD'S for approval. would like something that i can use later for cnc but that can do drawing of potential machines now . have noticed sketchup mentioned, not sure that is best solution , maybe there is not a program like i am looking.

Sienci
16-03-2016, 01:28 AM
Hey there,

Don't be afraid to start your own CNC project! Even it doesn't work out, you can always use the hardware you get to build something new.

Luckily there's a lot out there you can use to build your own machines.

I have a couple of things I have in mind that I found work well in my experience building bits and bobs.

First is use a GRBL controller (I would suggest TinyG or a GShield, or even a CNC Shield V3.0 if you're on a strict budget). These are easy to program and have a lot of support available.

For CAD software, I use SolidWorks. SolidEdge, Catia, are all similar tools. These are all really really expensive, so if you don't have access to them or at least the education copies, something like Autodesk Fusion is a decent alternative. The closest cheap Solidworks alternative I have come across is Cubify 3D. A 3D modelling software is hugely useful if you can assemble your machine before building it, so you can see where you're going wrong.

For your linear drive systems, I would suggest sticking to one type on each axis (although threaded rods/ballscrews almost always used in the Z axis). I think ball screws is a pretty good choice.

Good luck!

Andy

Clive S
16-03-2016, 09:17 AM
well , i gotta first thank all these peoples who build a wealth of information for people like me trying to get understanding in cnc
Welcome to the forum CHIphload you have come to the right place to find all the info you need your second option is the way to go, start by putting some drawings up to get feed back sketchup, Fusion360 are OK there are plenty of free cad packages around just do a search on the forum.

Please do not buy any electronics (especially kits) motors, screws etc until you have a design almost built.

When you are ready to start, start a build log to keep all the questions in one place.

Good luck with your build.

CHIpHload
16-03-2016, 03:26 PM
First is use a GRBL controller (I would suggest TinyG or a GShield, or even a CNC Shield V3.0 if you're on a strict budget). These are easy to program and have a lot of support available. i have not looked into electronics just yet , when i get to that i will probably build round digital drives like am882 or similar. so holding off purchase of anything like that just at the moment,though i am comparing some specs of controllers & drives as i go, thanks!

For CAD software, I use SolidWorks. SolidEdge, Catia, are all similar tools. These are all really really expensive, so if you don't have access to them or at least the education copies, something like Autodesk Fusion is a decent alternative. The closest cheap Solidworks alternative I have come across is Cubify 3D. A 3D modelling software is hugely useful if you can assemble your machine before building it, so you can see where you're going wrong. have noticed fusion mentioned though maybe there is something wrong with me , i am reluctant to use as along with other issue i have it is cloud based.maybe those who know will tell me this is the best option

CHIpHload
16-03-2016, 03:30 PM
Please do not buy any electronics (especially kits) motors, screws etc until you have a design almost built.

When you are ready to start, start a build log to keep all the questions in one place.

Good luck with your build.

thanks Clive , yeah, not buying electronics just yet, i do want to order screws, rails and blocks as soon as i can, would like them here before i start build slightly, unsure on pulley requirement re screw length. i am thinking would be better "FOR ME" with my nursery status in cnc , to actually build , then using a spring scale AND torque wrench(if i knew what size wrench) i could see what is required to turn ballscrews and move gantry

Clive S
16-03-2016, 04:39 PM
thanks Clive , yeah, not buying electronics just yet, i do want to order screws, rails and blocks as soon as i can, would like them here before i start build slightly, unsure on pulley requirement re screw length. i am thinking would be better "FOR ME" with my nursery status in cnc , to actually build , then using a spring scale AND torque wrench(if i knew what size wrench) i could see what is required to turn ballscrews and move gantryWell I would still get the designed done first as it could save you a lot of dosh if you buy the wrong bits.

nema 23 motors are the norm for this size of machine (low inductance) and 1610 screws x and y 1605 for z

CHIpHload
16-03-2016, 09:33 PM
1610 screws x and y 1605 for z

little experience here though i was thinking i might need 2510 ballscrews for X , though now i think 2010 suitable , i would have liked the resolution 2005 could give but thinking that might require to high RPM, i suppose some further plans need drawing up then i will take your sound advice for build log with questions in one place. gotta think more which direction i'm heading, just that i had almost been set to start ordering ballscrews & rail for option 1, though the more thinking "do i want to do this seriously?" option 2 seems more sensible . i have not looked at much depth into smaller precision aluminium mill type machine . the thoughts of coolant all over the place , or bits breaking an dinging the window through. yep back to the library for me

komatias
16-03-2016, 10:51 PM
Welcome aboard Chipload. Dont spend a dime unless you get a good design up. It will save you buying the wrong stuff.
There are now plenty of free CAD programs to play with but the one that I find offers the better deal/package is Fusion 360.

So best of luck with your endeavours. we will anticipate some photos in return for our collective wisdom.






Hey there,

First is use a GRBL controller (I would suggest TinyG or a GShield, or even a CNC Shield V3.0 if you're on a strict budget). These are easy to program and have a lot of support available.




Andy, with all due respect, Chipload wants to build a router not a 3D printer. And why program anything if one can just plug into Mach3 and be done with it?

CHIpHload
19-03-2016, 03:50 PM
Welcome aboard Chipload. Dont spend a dime unless you get a good design up. It will save you buying the wrong stuff.
There are now plenty of free CAD programs to play with but the one that I find offers the better deal/package is Fusion 360.

So best of luck with your endeavours. we will anticipate some photos in return for our collective wisdom.









thanks komatias, so many options ! i am trying not to be too keen . now im back to my original idea for wood router birch ply torsion box build , with all internal structure of constructed something like this, 17966as to build a torsion box with all internal squares the same will have more problems at a given freq according to what size squares and although while much easier in construction may not be ideal for this. i had thought same design as above hexagonal ribs for internal structure of bed, gantry also gantry sides and this appears to be backed up by by conclusion in Optimum column design using honeycombs (last link in first post) http://www.mycncuk.com/threads/5283-Interesting-Papers-on-heavy-duty-design-vibrations-composites-and-column-design. although i am far from being able to interpret if there is any actual construction detail (dimensional ratios). any interpretations welcome. i have also noticed CFRP (carbon fibre reinforced polymers) may be suitable skin for this type of construction and is also available as plate & woven carbon sheet although i'm not sure of methods of taking carbon sheet (pre pregnated?) wrap for gantry & resin up. has anybody tried this sort of thing or what do you think ?? the hexagonal parts could also be filled with say a mix of perlite and polystyrene balls. maybe also longways between two bed face's running through centre of hexagonal parts a bungee or some sort of rubber tubing (what tension?)

CHIpHload
29-07-2016, 05:36 AM
if any moderator could be so kind to delete this profile , as i can't seem to see an option to delete . THANKS