[Litemover]

Hi there,

I'm quite new to al this so you'll have to excuse my lack of knowledge here. But am wondering what the pros and cons would be for either a welded metal kit vs one that is machined to fit standard aluminum extrusion. Have seen a few kits around, all look awesome. I'm sure the extrusion is easier to assemble, but I do own a welder already too, so might be a viable alternative.

The machine I'm looking to build is at least 48x96", preferably 5x10' with a 5hp spindle and possibly servo drive.

Many thanks for the answers.
Cheers,
Chris

[Sinistersam]

That's an easy one to answer. Break out your welder. No way I would choose an extrusion over a welded machine.

[RossMosh]

Welding is a craft. Bolting extrusion together is not. So if you are a skilled welder/fabricator, welding is going to be beneficial. If you're an average Joe, extrusion is a blessing.

Combining welded elements with extrusion is also a very popular way of going about things. Weld up the base and then use extrusion to bolt the drive elements and rails to. It's a very solid way of building a machine.

[Litemover]

Welding is a craft. Bolting extrusion together is not. So if you are a skilled welder/fabricator, welding is going to be beneficial. If you're an average Joe, extrusion is a blessing.

Combining welded elements with extrusion is also a very popular way of going about things. Weld up the base and then use extrusion to bolt the drive elements and rails to. It's a very solid way of building a machine.

Are the gantry parts better to be extrusion or weld? I have a welder, and can weld, just need some practice.

Thanks for the info.
CC

[ger21]

Are the gantry parts better to be extrusion or weld?

That depends.

Generally speaking, a welded steel machine should be much stronger and more rigid than an extrusion machine. It'll also be considerably heavier.

But it's important to note that the design of the machine is more important than the materials used. You can build a welded steel frame from 1" tubing that may be weaker than an extrusion machine. Because steel is much cheaper than aluminum, you can use large, heavy wall tubing which is much stronger than extrusions for usually quite a bit less money.

If you look at routers in the $50K and up range, you won't find any made from aluminum extrusions.

I've seen many posts from people with gantry's that use a single extruded beam have deflection issues. A lot of early Joes 4x4 Hybrid builders have modified their machines to use two large extrusions to reduce deflection.

It seems like you want a very high performance machine. I think steel would be a much better choice. The issue you'll run into when choosing steel is that there are no real welded steel designs out there, other than the mechmate.

[port_huon]

For a welded kit in the size you mention, have a look at MechMate

[RossMosh]

Are the gantry parts better to be extrusion or weld? I have a welder, and can weld, just need some practice.

Thanks for the info.
CC

I can weld. I'd never build my own machine where I'm doing the welding. The fact is, the end goal is to create a high tolerance machine that works. I know if I'm doing the welding, it will never happen. Metal fabrication is a craft and I know I'm not a good enough welder, fitter, and fabricator. Remember, it's not only about welding when you build out of steel. You have to figure in how you're going to mount your drive and rail system. It's alot of drilling. A lot of figuring. A lot of fabricating.

A well made steel machine that is welded up is a superior machine to a bolted together machine out of aluminum. The thing I'm saying is, if you aren't talented enough to build the steel machine properly, your steel machine is going to be A LOT worse than an extrusion machine. Extrusion machines are A LOT easier to build right.

I'd suggest building something like this: http://www.cnczone.com/forums/cnc_wo...erparts-7.html

It's very similar to how CNCRouterParts, ShopBot, and EZ Router build their machines. It's a good way to build a nice light industrial machine. It won't truly compare to a $50,000 machine, but it will compare to a $20,000 machine and that's pretty good.

[Litemover]

That depends.

Generally speaking, a welded steel machine should be much stronger and more rigid than an extrusion machine. It'll also be considerably heavier.

But it's important to note that the design of the machine is more important than the materials used. You can build a welded steel frame from 1" tubing that may be weaker than an extrusion machine. Because steel is much cheaper than aluminum, you can use large, heavy wall tubing which is much stronger than extrusions for usually quite a bit less money.

If you look at routers in the $50K and up range, you won't find any made from aluminum extrusions.

I've seen many posts from people with gantry's that use a single extruded beam have deflection issues. A lot of early Joes 4x4 Hybrid builders have modified their machines to use two large extrusions to reduce deflection.

It seems like you want a very high performance machine. I think steel would be a much better choice. The issue you'll run into when choosing steel is that there are no real welded steel designs out there, other than the mechmate.

Thanks for the advice. I've been looking at the mechmate, and it sounds pretty good, just seems like it takes a lot onger to put together than the CNC router parts. Perhaps I ought to build s hybrid using some of the cnc router parts on a mechmate, hihi.

Definitely need the high performance, high accuracy, low deflection. Also am needing to put a 5hp 100mm spindle on it, not an 80mm spindle. The cnc router parts one looks really nice though. Could definitely make some use of it, just that after everything is said and done, it seems to cost considerably more than mechmate.

CC

[Litemover]

I can weld. I'd never build my own machine where I'm doing the welding. The fact is, the end goal is to create a high tolerance machine that works. I know if I'm doing the welding, it will never happen. Metal fabrication is a craft and I know I'm not a good enough welder, fitter, and fabricator. Remember, it's not only about welding when you build out of steel. You have to figure in how you're going to mount your drive and rail system. It's alot of drilling. A lot of figuring. A lot of fabricating.

A well made steel machine that is welded up is a superior machine to a bolted together machine out of aluminum. The thing I'm saying is, if you aren't talented enough to build the steel machine properly, your steel machine is going to be A LOT worse than an extrusion machine. Extrusion machines are A LOT easier to build right.

I'd suggest building something like this: http://www.cnczone.com/forums/cnc_wo...erparts-7.html

It's very similar to how CNCRouterParts, ShopBot, and EZ Router build their machines. It's a good way to build a nice light industrial machine. It won't truly compare to a $50,000 machine, but it will compare to a $20,000 machine and that's pretty good.

Thanks for the advice on this. I definitely have the experience and fabrication skills to weld and put together a machine, just been a few years that I've had to do it is all. I'm sure thought that it would be just like riding a bike.

Cheers,
Chris