Stretch a Joe2006 to handle a full sheet?

[Big S]

Hi All,

My first post on this forum , I am wondering about the feasibility of making a CNC wood router in Joe2006 style but able to cut a full 4' x 8' sheet to better than 0.1mm accuracy and precision.

Just wondering if MDF will have enough stiffness for a machine this size? Also what other obstacles can I expect in relation to the standard version.

I plan on a few design changes, I like mhiggins idea of the V slot in the gantry instead of the exposed ribs. I also plan on making the side bearing carriages out of aluminum to increase the rigidity. I will probably use a rotating nut on the x-axis to stop the leadscrew whipping over such a long length.

I would like to keep the cost down as much as possible (don't we all )

I also have access to a CNC router to cut all the parts on.

Shannon.

[ger21]

I've never looked closely at Joe's plans, but wouldn't you need to build a roughly 5 x 10 torsion box, which would need to be stiff enough to not sag at all over the 10 ft span? It is only supported at the ends, correct?

[wcarrothers1]

I would say you will not be able to come near .1mm accuracy in that design if you were really talking about .1 and not maybe 1mm or something.

b.

[Big S]

Thanks for the comments guys

I think if it had a scaled up torsion box that it would be strong enough (think a large Joe2006 but with a slighty lower gantry)?

I have read that the Joe2006 is good to 0.01" or so, why would it be a problem to achieve this on a bigger machine?


Shannon.

[jsfjet]

Shannon,
You may want to look at Slosylva.com belt table design; I still don’t think that would cut a board of that size though accurately and of course you would have to modify the legs etc. I’m about 70% completed on a 27.5 * 64 inch cutting area its heavy as hell. I am just waiting on my belts and pulleys from econobelt to finish it up test (i.e cut some of the router parts accurately to replace the hand cut ones) it dismantle it and paint it. I’ll let you know the accuracy.

Regards,

Mark

[joecnc2006]

Well i have looked into and even drawing and building it to a 4'x8' cutting area. I have come to the conclusion a router that big should not be build from wood, if you plan to do anything other than cabinet doors or such plain wood working.

That being said... I Am in the proccess of building a new machine.

"Joe's CNC Machine (Hybrid)"...... Comming to a CNC Zone near you. I think people will find it interesting.

Joe

p.s. (No, I do not plan on releasing any info or anwsering question about it at this time.)

[Big S]

Hi Joe,

I was planning on using it for basic woodcutting and not much more, I have available, and will build smaller CNC machines for metals and things that need to be more accurate.

Mark,
Do you have a link to the site as I tried google and it came up with nothing.

Thanks,

Shannon.

[jsfjet]

Shannon,
Sure here it is



Regards,

Mark

[jsfjet]

http://solsylva.com/cnc/1aplanshome.html

sorry

[ger21]

www.Solsylva.com

Another thing to consider, is that the typical good quality acme leadscrews we use, are only accurate to ±.009/ft. In reality most are much better than that, but worst case could get you a screw that it off almost .5mm in 2 ft. That makes it much harder (expensive) to be within .1mm in 8 ft.

[Madclicker]

My machine is pretty big and made of torsion boxes. It cuts 50" x 34". The 50" is across the gantry which is 65" wide overall. The bed TB is 4' x 4'. I didn't make any attempt to lighten it and I can tell you it was a real bear to get the base put together. Had to use a floor jack a couple of times.

I can cut to .01". I just measured what was supposed to be a .75" dado and it was .76".

I think I could have built it to cut 50 x 100 if I had put some really good engineering into it. I would probably use 1/4" MDF with lightening holes held together with epoxy. Gonna take a really big, and really flat assembly table.

Anyway, mine has done what I needed it to do for over a year now.

[Big S]

Thanks everyone,

How about if I made a (large) MDF box and turned it upside down, the top would then have a structure similar to Joe's machine but without the lower part of the gantry, and using dual belt driven lead screws for the X-axis (like on solsylva site)?

My brother uses a Multicam router for his job, that machine is able to cut a full sheet, so we would cut the parts out on that.

Madclicker,
do you have a link to pictures of your machine, or a thread on it?


Shannon.