Tumbler Build - For cleaning plasma cut parts.

Could you do a sketch of what you think a VMC frame would look like from tube? What size tube would I use? Rectangle or Square?

depends on how much foot print you can live with and what kind of travels you are looking for? Z height would be an important part of the needs list.

a fixed bridge is going to be more rigid but the foot print is bigger since the table moves. the typical average VMC is not huge as far as travel goes. the average size VMC might have 24" x 48" of travel on the X and Y axis and maybe 20" from the spindle to the table. so they are not huge on travel but are rock solid because the base is cast iron and weights a several tons with the table usually cast iron as well on the commercial machines.

if you built a gantry mill where the gantry moves you can get a 5' x 10' X and Y axis easy enough but the Z height is going to be tough to get very tall since the higher you go the harder it is to keep things solid.

i think with a welded tube frame the shape of the tube is not that critical, but since it would be filled something rectangular might be better on a longer span. the epoxy does shrink some but it is a very small amount (.001 imperial seems to be where most fall ) i think as long as the tube is thick walled material at least .188 or better things should be pretty solid filled with E.G.

you gain some rigidity from E.G. but i would design the frame to do the bulk of the support. the E,G. makes the frame more like cast iron because the tubes can no longer resonate because of the fill and act more like a cast iron base casting of a VMC.

so the size of the work area is going to be a big factor of what you need to figure out so you can build the machine to suite your needs.

then you get into spindle considerations based on what you want to cut after this. so there are a lot of things to think about first.most commercial VMC usually come standard with a 10,000 rpm spindle. high speed spindles can be good for some things like Aluminum machining since really high speed spindles can let you approach things are really high feed rates. but if you get into the steels you can't run that fast anyways so this is probably why 10,000 is standard and a happy medium on most commercial VMC machines.

I would be happy with 24"x48" (600x1200mm) and I want to machine steel.

I was thinking of the plasma sludge and I think I could strain out the large chunks of steel easily and dry it. I am sure it would add a far bit of weight to the frame, I am happy to give it a try.

I just cant imagine how I would go about making the frame out of tube, would I butt a couple of pieces together and weld them then machine the top and bottom flat?

there was someone over on cnczone that did a linux build i was impressed with the concept. he did a open rib arch design that was E.G. filled that was a moving gantry design i think. i will have to see if i can find it and put a link up for you. he was doing machining on everything it worked that well.

any design that uses the frame work as the mold would work well. it's just a buggers to remove and if you pour and let set and are done with it saves on the cost. materials for a mold add up to extra cost.

i will look for the build i am thinking off though and post a link.

this was the one i was talking about. this tread is actually two builds in one. the first small machine does really well with high speed machining of Aluminum for a DIY build. but if you look through the tread the gantry is filled and the tube frame is filled with E.G.

the machine has a nice high speed spindle so it does Aluminum well. the only thing that is not good is the lack of lower speeds with usable torque with that type of spindle. rigidity wise the machine would handle mild steel i think just would not get very good tool life running that fast. that was why i traded off the high speed spindle choices for what i used. i can't go nuts with light fast tool paths but i can get into slower cuts with a little more step over.

spindle choice is important based on needs you might have. and tool life is important since tools are not that cheap. so you want to get the most out of them to keep things cost effective. insert cutters are nice but they like brute force to drive them around.so that's where spindle HP comes into play.

www.cnczone.com/forums/uncategorised-met...lling-aluminium.html

With the T Slot table that the parts to be machined sit on, can I buy them or do I need to make one? What are they called?

tommylight wrote:

For that size, something like 600x400x10 to 15mm thickness would be nice,

Spoke to my steel supplier and the largest tube I can get is 400x200x12.5. I might have to make a welded tube from plasma cut plate. I can make it any size I want if I do that. I really should not go off on tangents until my other projects are finished!

t slot tables can be bought but they can get expensive going that direction. as far as work holding goes you can do that may ways. most common way is vises but like i said it can be done many ways based on the type of work you are doing.

the t slot tables just act as the attaching point for your work holding. they sell basic clamping sets for the size of t slot that is on the machine.the picture below is about as common as they get. this is what is used to hold the vises to the t slot table often.

Would you recommend buying a table to suit my machine from China or should I buy some colded rolled flat bar and make my own? I do have access to a manual milling machine.