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Screen designer tips and tutorials / Re: Screen Button Libraries
« on: April 09, 2016, 03:34:51 PM »
Thanks Gerry, I'll look into Realdraw.
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My apologies for winding you up. That was definitely not my intention. Believe it or not - I was trying to clarify something.
I've attached a (crude) schematic of one of my routers. To give an idea of scale/size, the gantry is approximately 4 feet long.
Now this MAY be an unsuitable design for your purposes for details yet to be disclosed - but what I was trying to clarify/get across is that this does not have two TABLES - it simply has a master and a slave axis. As you can see the gantry is fully supported and hence there is no sag.
Anyway - as sometimes happens when conversing with text - what should have been a small point to try to clarify, has taken on a life of it's own beyond its usefulness - so I'll back off and leave you to it.
Again - My apologies for winding you up.
I think I can see the target here - you want to build a pipe bore scanner that has a travelling head on a support that runs up and down the centre of the pipe?
You want to control the vertical and horizontal position of the scanner within the bore?
If so then its an interesting project
In my mind, X axis is the scanner head, Y axis would be towards/away from centre of pipe, Z axis is up/down from centre of pipe. This would be with my view having the pipe running left to right.
I would have my X on a removable support track, probably belt driven or nylon rack & pinion for weight saving, this would simply sit in two supports, one at each end and have both ends running slaved Y & Z motors so they track each other and keep the X axis / scanner support true to the bore of the pipe.
Am I following?
How big is the pipe?
It just sounds like two vertical X/Y tables facing each other and running slaved motors on both axes, apart from the mechanics, probably quite easy to do?
Obviously all we need is a travelling linear device - could be a trapezoidal screw in the vertical plane running on a linear rail, doesn't sound like there is a need for any serious rigidity or speed here. No idea how fast the scanner runs though??
Just thinking out loud
OK - I think I see where the confusion started here.
In your original post you started off saying:I need someone to point me in the right direction for controlling two stepper motors on one axis and keeping them in sync.
So far so good - this is the way you need to go (as I've been saying) - you've been given the answer already - slaving.
But then for some reason which I don't understand - you said:I am building 2 XY tables that will be separated and I need them to work in sync.
I'll try once more - a STANDARD XYZ gantry machine supports AND drives the gantry at BOTH ends. Try googling "gantry router pictures".
Your labeling is probably guided by your familiarity with lathes. But if you swap the labeling for X and Z you have a standard XYZ gantry layout. Two slaved motors for Y and single X and Z. Sorry - I don't see a problem here. All pretty bog standard stuff. What am I missing?
Picture a 12 in DIA tube, 6 ft. long with an X-Y table at each end that will position a bar in the tube. A probe runs along the bar (Z axis)
to scan the inside of the tube, thus mapping the magnetic field. Positioning on X, Y, and Z.
Why do you need TWO XY tables for this?