Thank you Rich and Hood you guys are quick to respond!
I have been working on the calculations for the x axis.
It will need to be about 4000mm wide
Made from 2 lengths 250 x 150 x 5 RHS spaced 300mm and joined with 150 sq tube and the ends welded over and fully joined.
There will be 2 type 25 rails mounted on each beam giving 4 in total.
Compared to machining or routing sewing has the need to have a tool on the bottom and the top of the cloth hence the need for the large vertical O frame to pass the work through.
I calculated the deflection (Simply supported at the ends only) to be about .211mm with a 40kg load in the centre (The moving head) and the distributed load imposed by the rails about 10 kg per metre. The frame has to be really stiff the load is small but there will be resonance. I wish I had better software, and a younger brain.
Not bad for such a large span.
I used a handy tool to do a quick deflection calk called Beam boy.
I found it at:
http://www.engineers-international.com/freeshare.htmlIt works quite well I am sure there are more advanced tools so if you have one please post a link.
250 x 150 x 5 RHS weighs about 29.9 kg per metre add to that the rails and the sewing head and we are moving about 350kg to 400kg
For a standard 4000rpm sewing machine we need a feed rate of about 233mm per second max. That is a fair amount of weight to push around; it will need some meaty drives. (I think I will drive it in tandem from the ends). Unlike metalworking the positioning accuracy required is around .5mm, (approx 20 thou imperial).
The frame with the sewing heads not included there we need a couple of thou max error along the x axis.
Sizing the drives is not going to be easy for me. If there is software out there in cyberspace to assist I would really appreciate hearing about it.
Usually the first iteration of a new design is doomed to be changed, but so far its looking good.
Cheers
John Mac