Comments on my first attempt at a design (if you would)

[lukekjackson]

John11668.

I wonder why you felt you needed such column height relative to your X and Y dimensions . What height of components do you envisage .

In short i didn't really decide on relative dims, i wanted to upgrade the Z on my CMD10 so bought a a X3 column which has far better proportions than the stock CMD. While tapping for the linear rail fixings messed up a couple of holes and snapped a tap in 1 so i bought another one. Then as i had 2, I thought if I fix them side by side its even more rigid. once i modelled this up it looked ridiculous in comparison the the X/Y table (already replaced from the original CMD10 one). so whats the the obvious next step, start on a new X/Y of course. It is a slight case of scope creep from the original intent


What is the maximum height of your proposed component? Work from that taking into account the Z positions for clearance and depths of machining operations , spindle retraction etc . Tall components will need to be braced from the table so add to the need for table width and extra rigidity. - I have been thinking about this and you are correct i cant see myself ever needing to mill the top of something 400mm + high in a serious way. What i could imagine though would be drilling or flattening an edge. I'm effectively thinking i may mill up to a couple hundred mill high and only drill above that

Would it be worth losing the risers, i just didn't like the idea of having unusable rail under the lowest point the head can reach. and if the highest point of the Z axis is rarely gong to be used or only used for drilling does it matter if when using that section it is not as ridged as ideal?

Looking at your design I see an X / Y table sitting on a flat base . You could save yourself some time by buying one of those and adding the ball screws and motors which was the route I chose to take. OK so mine may not be the prettiest in the world but I wanted to get quickly to the eletronic/ software stage and start to play. - that was my initial plan and i did buy a larger X/Y table, i Want to add linear rails and ball screws though and when i though about what i would have to do to the X/Y, and how i would do it only having access to the CMD10 to do the work it seemed like it would be more effective to use a surface plate and ground flat stock to build one. It would save me a lot of machining squaring things up in theory. I have no doubt i will live to regret that.

Hanermo mentioned Deckel Aciera and Shaublin , all good examples of well designed column mills from which design lessons can be learned .
I used my Deckel FP1 as a base , but as they say on the BBC , other makes are available . You will not find anything more rigid upon which to base your build - Just had a look at the FP1, that does look look like a solid lump. To give me some frame of reference what depth and speed of cut would this sort of machine regularly make in steel. the Belt drive I've included will take the spindle speed up to 10K RPM so i'm of hoping to use smaller cutters at higher speeds to make up for the lack or rigidity of not having a big cast base