Hi,
try searching for a 'rotary coupling' or 'rotary union'.
'Sensibly priced' is highly subjective.
Craig
Hi,
try searching for a 'rotary coupling' or 'rotary union'.
'Sensibly priced' is highly subjective.
Craig
Hi Craig, I could be mistaken but I don't think the cylinder needs to be able to rotate with the shaft necessarily? Basically the drawbar has a cutout in the spindle shaft where the stock setup passes a pin and a sleeve that needs to be pressed down to release the drawbar. The sleeve and pin would need to rotate with the shaft but as long as said release mechanism has a spring return or something with clearance that "stays out of the way" while the spindle is at >0 rpm, it doesn't necessarily have to rotate with the shaft I think? Not a lot of room either way, since there would need to be a flexible coupling of some sort at the top of that shaft in the picture to connect to the servo output shaft.
Hi,
most empathically the cylinder does not rotate, its not even close to balanced. The cylinder must remain stationary, and yes the piston must retract so that the actuator shaft (of the piston) does not bear down
on the drawbar while the spindle is operating.
My new spindle has a double acting piston, or actually three pistons in series if the truth be known. When the cylinder is active the pistons bear down on the drawbar to release the tool. When the cylinder is inactive
the pneumatics are such that the pistons withdraw and thereby leave a mm or two clearance between the shaft and the drawbar.
I your case with a direct coupled servo either the shaft of the servo needs be hollow that the ATC piston actuator shaft can pass through the centre of the servo, OR, the ATC cylinder must have a bore though the centre.
Neither sound likely to be available.
The only other way I can think of is to have two cylinders parallel but symetrically displaced from the centre line of the spindle with the drive passing through the center of a yoke between the two cylinders. The yoke would bear down on the
draw bar.
Craig
Yeah, doubt hollow servo motors are a thing. Hollow/through bore pneumatic cylinders are actually a thing, although many options are too bulky and/or expensive. Mack Corp in the US makes some that would at least roughly fit the bill (see attachment). Main issue is that they seem to be a fairly bespoke part so probably won't find one with the right dimensions second hand on ebay. Did also arrive at the plan B of somehow pushing down from two sides.
Bit of a plot twist, I was procrastinating pretty hard on the frame design. Then my eyes fell on an old shaper for sale and one thing led to another...
I only plan to use the base and the main frame of the shaper. As a bonus there are already some rough X Y Z reference surfaces, although there is a decent amount of wear in places of course.
Hi,
its bloody hard to beat old cast iron like that. Its as tough as hell, stable and rigid.
I would not concern yourself with the wear in the beds, what the bet it is only half-a-thou or so anyway. Get your machine working and then maybe consider scraping the ways flat.
To make it perfect paint it pink with little flowers on it!
Craig
Some drafting of a Mori CMX inspired design. The corner posts are just for guesstimating an enclosure footprint.
Hi,
looks good, could only improve by being pink!
Craig
Hi ook - Its looking good but be careful with the webs on the bed, they can vibrate. If you can do FEA have a look at modal analysis this will identify vibration modes. Peter
Hi Pete, I ended up taking a shortcut on the mill table, a big cast iron right angle milling fixture came up on Facebook Marketplace and I couldn't resist it. Dimensions aren't perfect for what I want (about 600x240mm work area, 300mm height on the mounting surface) but it should save me a lot of work making something similar out of plate steel.
Hi,
no matter whether it's made of steel or cast iron, the Tee-slots are the key to versatile work holding.
Many people end up with a flat table but no real way to attach vises or workpieces except maybe a network of threaded holes....'useless as tits on a bull'.
Craig
Matara UK have a lot of blogs that are informational that i find really helpful. they specialise in Linear motion and pneumatics. I recommend you have a look - https://www.matara.com/