Materials used in CNC build projects

[Ross77]

Hi George

I'm going to steer clear of the vibration stuff untill I understand it a bit better. But listen to Irving and Freddie and dont use rubber at all.

I kind of agree with you about reducing the vibration but the only way I can see to reduce spindle and motor problems is to use mechanical counter shafts and balances like in a car engine or tuned mass dampers but thats all getting very silly and complicated and I will definatlly be shot for suggestting it.....

Its sounds to me like you are at the same stage as me when I asked if it was possible to convert a pillar drill to a mill. Every one said no dont bother its too much work, but I went ahead and did it anyway ......... and yes it was a lot of work and still isnt fully sorted but I have learnt so much in the process. (and I wouldnt bother again) If its only your time then you have nothing to lose.

At least it would end the debate .......

[GeorgeD]

Florin,why did you do that? ie quoted my text as if thats what I was actually saying.

I was just putting my thoughts across and thats all they're.

Cheers.

I'll leave the forum and go elsewhere.

Irwin thanks for all the time you gave me on getting this far,much appreciated.

[florins]

Florin,why did you do that? ie quoted my text as if thats what I was actually saying.

I am sorry George, but it is quoted from your previous post (post #29)... maybe I misunderstood what you tried to say.

In my opinion, as a physicist, a good model replicates very well the reality, and this is the base of all human progress in the modern age. Instead of MAKING the mistakes, you can MODEL and avoid them. That's maths and physics good for.

If you can not model them yourself, you should trust the more experienced persons. Otherwise, you just waste time and money, but as Ross77 said, this can be educative.


All the best.

Florin

[GeorgeD]

I've put the idea of using perspex to bed for the CNC build and opted for mild steel box section tubing, somewhere between 3mm and 4mm wall thickness.

Have purchased a mig welder,should arrive Monday? the thing that I now need t decide is to whether to have the gantry static or traverse?
Someone on here posted a link to a machine that was also done with box section mild steel and thats what swayed me to build it in this material,it wasso nice I wanted it. :)
Intentions of this build was to use as a router/carver and with future components changed for better quality this was the ideal material to use for heavyish work?

I won't be aquiring the box section for another week or so? but this will give me adequate time to get to know the Mig,had a go at arc welding in the past but that died a death due to me getting flashback at sometime during the usage of the arc welder,terrible thing to happen as its really very hurtful on the peepers for a day or two.

[florins]

...opted for mild steel box section tubing, somewhere between 3mm and 4mm wall thickness.

Fantastic George, steel is a much better way to go! Good luck in your project and keep us posted!

Florin

[GeorgeD]

I figured its much easier to cut,construct and weld the frame in mild steel than it would in working with Aluminium.

I also worked it out the price will be lower than Aluminium going by the prices on ebay offcuts that sellers are offering,but not only this it is does truly look better in mild steel.

[routercnc]

Nice one, glad you persisted with your plan to make a CNC machine. Steel is a better option.

You can use all that spare perspex to make:
Dust extractor plate, to attach a vacuum to
Safety screen
Side and end pieces around the cutting area to protect the bearings, drive system etc. from excessive dust
See through lid for your control box
etc.

Your choice of static or moving gantry depends on how much area you have in your workshop for the machine, because the static one will need about twice the area compared to a moving gantry type. Your choice might also depend on what you want to make. For example,
For small (say 400x400mm) very intricate work, a static gantry could be a good choice, because it can be made very stiff.
For larger work, there often isn't space for a static gantry, and the same level of detailed accuracy might not be required. A moving gantry is then often suitable.

If you go for the moving gantry, there is another choice to be made depending upon how wide it is. For wide gantrys, say >500mm, you might want to drive each leg directly rather than a central drive underneath. This is to reduce the risk of racking where the gantry skews to one side under load.

Good luck !

[Colin Barron]

Aluminium may be an easy material to work with but in industry steel and cast iron are the prefered materials for machines. I would have thought that steel u section and box section would have been the prefered diy material because it is easily joined and heavy so has less vibration.