Gotta start making a CNC router

[vegeta]

Well I've been busy constructing the house been really busy sorting out my career but never actually taken the time to use these skills elsewhere. Been studying the arts of D&T for 6 years of intense study and got all sorts of qualifications, so i'm now gonna put them too the test.
Been sharking around for logs of people making CNC routers, phoning Scrap metal merchants for box section etc. Even baught a book how to make one so last night instead of doin my work I plunged into my modelling software to see what I could come up with.

My plan is to have box section steel as the main frame work, with stainless steel bars for the X,Y and Z axis. All sliding on plain bearings. My design is to keep all the axis high and out of the way of the shavings and swarf this beauty will hopefully make. And if the gantry ends up half as shiny and nice as my design it'll all be gravy

[ViperTX]

Welcome....I'd box in the upper section...or at the minimum connect the triangular pieces to the vertical corner pieces at the top.

[Greolt]

As drawn the X will rack as the Y moves to one side or the other.

Good to have made a start though.

[Oldmanandhistoy]

Hi and welcome to the Zone,

How do you get your materials in to cut without banging your head?

John

[project5k]

i too see a racking issue, perhaps adding either longer linear bearings, or a second set... really if you wanted to really eliminate the racking put a screw on each end of the x.... also, i see a twist issue with having the x axis bearings off to one side like that... other than that, a pretty nifty idea...

[wcarrothers1]

Well becides the loading issue above.. I see clearence issue between what ever/ how ever you might mount the Z axis and the X screw. ie when Y travels right to left it will get in the way of the x screw.

Course then again maybe you will build z more compact. When mine is full up my Z motor is pretty high up since it's in line with the screw and all.


depending on how long your Y rods are I'd say them not being supported could add more flex then you might think as well. I know I started out not supporting mine and added them later although my 1" rods were 60" long.


b.

[vegeta]

Thanks for all the interest , very responsive, in particular regard to the quote in this title. Thanks for your constructive comments, as a result I have rethought my design as I too was thinking about the load acting upon my x axis. Looking further into this I decided to add a second set of bearings to run along the shaft creating a 4 point base of support on either side of the gantry.

To tell the truth I was unsure of the stability but decided to post what I had anyway

Oldmanandhistoy Apprentice

Thanks for your response, err was planning on just sliding the work peice into the base then clamping it externally dont think I need my head in there, but thanks I did laugh (hope you were having a laugh anyway )

But thanks for all your interest and ViperTX thanks I know what ya mean im probably gonna strengthen it depending on how sturdy it seems but gonna print off my individual component orthographics and go ahead with it as is, I can always refabricate once complete as wcarrothers1 was saying.

Find attached pictures of the modified gantry with different views of the z axis in different locations

[Oldmanandhistoy]

Hi again,

Yer was jesting about banging your head but I do see issues loading and clamping materials. What are you looking at cutting area?

It’s the accumulation effect that is going to give you the most trouble as I see things. Such as your X axis screw supports and the cantilever effect of the Z axis. The distance between the cutting point and the Y axis rails will cause twist while cutting. This and the pushing forces on the X axis together will imho cause the cutter to deflect.

What materials are you planning to cut?

I understand your reasoning for keeping things away from the chips but with the X axis rails and screw under the table and the Y axis above the cutter as in the more conventional designs I don’t see the need to be so radical with your design.

I have a cnc router and the only problem I have is with dust accumulating on the Y axis rails and screws and the dust will get there what ever the height of the design.

I don’t wish to sound critical just trying to help if I can as others have helped me.

John

[yukonho]

Vegeta.
Your machine looks like it will be very wobbly. Long unsupported rods will flex a lot, the plate you have holding the rods will flex too.
Also, it will be difficult to load and unload your workpiece.
You obviously have some good CAD skills, I suggest looking for a way to support those rods, perhaps go with double leadscrews, one on each side, to eliminate the triangle bits that hold the one leadscrew.
Also, your Z axis is hanging way out there, look for a way to make it more compact.
If you are going to use steel, you may as well make the best use of it, and have a rigid machine.
colin

[vegeta]

Hey guys yep well I took into account all of whats said and I am thinking as we speak, being a D&T man i'm always thinking outside the box for inovative ideas I guess I thought too far outside the box ha.

Well I have hunted around for other designs and took notes of the one i'm using in school. So I'm gonna get on my drawing board and create a solid idea, I always think so much better with a pencil in my hand, so stick with me guys theres lots more too come I'll be scanning my designs into the comp for you all too see.

Here's some ideas I found and will be using these as I design for my new improved CNC router, thanks yukonho will do. Congratulations on the new baby

[Oldmanandhistoy]

I for one will be watching to see what you come up with; I like new ideas.
D&T = design and technology?
Just glad we could rein you in (just me jesting again).
New methods of building can on occasion spark some very good ideas; keep up the good work.

John

[wcarrothers1]

good to see you altered course..

It's easy to think rods will be stiff but they do flex. With out adding the support between my 1" rods my design would have never worked well. Becides I'm sure you can find a less expencive design then one that used 6 rods..

Course I'm convinced my router mill design could be one of the better ones and it didn't use what I would call a very common method (v grove bearings on box steel welded to c channel) for support and movement of the gantry up and down.. But it sure does work..

Anywho..

b./