Bedframe design idea

[liquibyte]

How does this look for a bedframe rails design? I'm trying to do a design as cheaply as possible. I have an old cot frame with a trundle under it that my girlfriend was going to throw out when inspiration hit. Basically the table/x axis frame, gantry frame (movable) and y axis frame should turn out to be 99% free. The only problem I forsee is getting the steppers on either side to sync properly. I know it's not to scale, it's just something I threw together in qcad (yep, another linux user) and to be honest I've never used any cad software before. The way I see it, the gantry will be 28" on all sides with the table itself being 56" overall in length and around 30" to 34" wide. I plan on putting the ganry together first and build out from there.

I forgot to mention that I plan on using this first one to build a smaller one for pcb's and then on to perhaps a nice aluminum project (I can dream right?).

[liquibyte]

I just realized that I should have attached a picture too. Sorry about that.

[harryn]

Hi, Interesting design. I am also a beginner, so take this info with that in mind.

a) Stepper motors direct driving the pinion
- I am (planning ) to do the same thing, and mechmate builds also do that.
- Keep the pinion rather small to maintain torque from the motor - and don't go for a wimpy motor or it will skip steps under load.
- There are some various vendor links in my attempt at a build log
- Getting two motors to sync is not a problem - mach can do this for you, but plan on needing a driver for each motor

b) Rollers
- It is easy to draw rollers mounted in a straight line, and really hard to actually accomplish this, especially when you try to constrain the movement of an axis in 3 D
- You can get some ideas from the linear carriages sold by cncrouterparts.com

c) Spring Load on the rack and pinion
- Since the movement is never perfect and rails are never completely straight, it is common to sort of spring load the gear / pinion against the rack. Also a bit of a pain.

BTW - The frame is the cheap part - the real money is in motors, drivers, and other electronics.

[underworld]

I am a TOTAL noob to all this, but I have to say, I like your creative thinking
I hope it works well for you!