CNCzone.com-The Largest Machinist Community on the net! - Linear and Rotary Motion http://www.cnczone.com/forums/ en Sun, 22 Nov 2009 21:28:20 GMT vBulletin 60 http://www.cnczone.com/forums/images/misc/rss.jpg CNCzone.com-The Largest Machinist Community on the net! - Linear and Rotary Motion http://www.cnczone.com/forums/ Which design would you chose for my router http://www.cnczone.com/forums/showthread.php?t=93697&goto=newpost Wed, 18 Nov 2009 19:05:01 GMT need some help here from you guys with more... need some help here from you guys with more engineering expertise than me.. I'm building a home built CNC router, hopefully with the ability to machine hardwoods somewhat reliably, I'm planning on using the router for a lot of guitar building and such.. so it has a long Y axis 55" ( 49" travel) or so and a moderate X axis 24" (19" travel) and around 5" of Z travel hopfully.. Anyways I'll be using some supported 20mm rails and blocks for all the axis with dual ballscrews on the Y axis and single ballscrews on the X and Z..( not in pictures yet because I'm decideing how to mount them..

Anyways.. my real question really is.. I have 2 design possibilities for the X axis.. after looking at these 2 pictures.. what would be the better setup.. the under and over configuration I figure would bring the router in a little tighter to the X axis gantry and would spread out the width of the bearing load on that axis.. any input would be appreiciated before I start the build.. ( the parts are coming soon..)

Aloha..,

Del
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]]> Linear and Rotary Motion konalure http://www.cnczone.com/forums/showthread.php?t=93697 linear rail binding http://www.cnczone.com/forums/showthread.php?t=93636&goto=newpost Tue, 17 Nov 2009 23:34:55 GMT I got my hands on a belt driven actuator. It has... I got my hands on a belt driven actuator. It has thk sr20 rails with 3 blocks. The blocks are mounted on an inch thick piece of steel. In my infinite wisdom and desire to use the blocks on another rail, I removed them from the steel mount. When I put them back on the mount and install them on the rail I now have some slight binding.

My question is - how do I get rid of this binding?

I've tried installing the three blocks on the rail and then fastening the mount to them by incrementally tightening each bolt (there's a total of twelve) as I force the whole assembly laterally by hand against the rail in an effort to line them up.

Do I need a torque wrench for this?

Could this big heavy piece of steel that is my mount actually be bending when I tighten the blocks to it?

Thanks for any advice.
Pedro ]]> Linear and Rotary Motion funkenpedro http://www.cnczone.com/forums/showthread.php?t=93636 First post - linear drive systems costs http://www.cnczone.com/forums/showthread.php?t=93423&goto=newpost Sat, 14 Nov 2009 06:35:09 GMT Hello everyone, this is my first post on this... Hello everyone, this is my first post on this forum. I am very interested in building my own cnc router and i have being doing some research through the internet lately.

I would like to build a cnc router with a cutting area of x=4' and y=3', which linear drive system would be more suitable for this router in terms of cost (as of nov-09), considering that i am not cutting parts for a space telescope :) :
1) chain drive
2) belt drive
3) rack and pinion
4) ball screw
5) lead screw

regards ]]> Linear and Rotary Motion rdcd http://www.cnczone.com/forums/showthread.php?t=93423 <![CDATA[another servos V/S stepper V/S R&P V/s ballscrew thread]]> http://www.cnczone.com/forums/showthread.php?t=93339&goto=newpost Thu, 12 Nov 2009 20:05:30 GMT I was convinced to go with R&P and steppers.After seeing Granite Devices servo drives changed my mind.
With R&P it appears 20to 1 gear reduction is necessary with servos while with steppers a simple 3to1 belt is sufficent.
Rather than go on and on.
R&P is for steppers.
Servo is for ballscrews with the pitch required.
Larry ]]> Linear and Rotary Motion lgalla http://www.cnczone.com/forums/showthread.php?t=93339 Bad Ball Screw? http://www.cnczone.com/forums/showthread.php?t=93332&goto=newpost Thu, 12 Nov 2009 18:54:40 GMT We have a Makino FNC74.The Z axis is giving us... We have a Makino FNC74.The Z axis is giving us problems.When machining
apart,the "Z" will go .012 deeper than it should.The read out reads the currect number,but the part is out of spec.
We used a dial indicator to check for this problem.What we found was at
a slow feed rate the "Z" was dead on everytime.But when we increased the
feed rate,the issue with the .012 returned.The readout reads the same every single time.and it does not change as the "Z" comes down.So I know that the Ball screw is not turning.
I was told that this could be caused by a bad Ball Nut.That at a higher feed rate,the balls move slightly.but then relax causing the "Z" to come down.
Is this true,or am I over looking something?And is there a way to verify that the Ball Nut is bad? Thanks ]]> Linear and Rotary Motion Katoom http://www.cnczone.com/forums/showthread.php?t=93332 Hollow Shaft Servo Encoder Motor http://www.cnczone.com/forums/showthread.php?t=93232&goto=newpost Wed, 11 Nov 2009 06:51:42 GMT I have been looking at the Allied Motion CM-900... I have been looking at the Allied Motion CM-900 brushless hollow shaft servo encoder motors for driving screw shafts on 3" diameter x 12" length 1,000ml piston ballast tanks for rov submarines.The water pressure inside the piston is 10psi and the total piston travel should be less than 30 seconds.The motor will have forward,reverse and position memory.Has anyone had experience with these types of motors ? ]]> Linear and Rotary Motion sunworksco http://www.cnczone.com/forums/showthread.php?t=93232 GMT Ballscrews + Poll: Double vs. Single Nuts http://www.cnczone.com/forums/showthread.php?t=93136&goto=newpost Mon, 09 Nov 2009 19:21:03 GMT We'll be introducing a line of rolled ballscrews in the near future as well as other linear motion components.

The ballscrews will be rated C7, and will be polished for smooth motion. The ballnuts are sealed with internal return tubes. They will be available in 20mm (12, 18, 24, and 36" lengths) and 25mm (48, 60, and 72" lengths).

The ends will be pre-machined to fit BK/BF and FK/FF style support blocks with 15mm and 17mm ID 72XX and 62XX bearings (which we will also offer).

For ease of installation, we'll have zero-backlash double ballnuts available for the same price or less than what one would normally pay for two single ballnuts (in the $100-$140 range). Would anyone here still be interested in single ballnuts?

-Sol
Glacern Machine Tools

A sample 25mm GMT ballscrew with single and double ballnuts.
]]> Linear and Rotary Motion Glacern http://www.cnczone.com/forums/showthread.php?t=93136 some rack questions. http://www.cnczone.com/forums/showthread.php?t=93031&goto=newpost Sun, 08 Nov 2009 00:57:15 GMT 1.) What are the benefits of using steel gear... 1.) What are the benefits of using steel gear rack vs brass? beneficial property's of brass racks?

2.) What is the best y axis mounting configuration, and do most people Bolt through the side of the rack or clamp the rack into place?

3.) Rack module measurement, what is being measured?

4.) Is there anyone using helical R&P should i choose this over the spur gear ?

Any additional information on optimal Rack and Pinion setups will be appreciated. ]]> Linear and Rotary Motion blazedforever http://www.cnczone.com/forums/showthread.php?t=93031 Cam Machining http://www.cnczone.com/forums/showthread.php?t=93029&goto=newpost Sat, 07 Nov 2009 23:53:27 GMT I am having an difference in opinions. We have... I am having an difference in opinions. We have an old blueprint of a cam. We need to make a master for the cam. The drawing shows the cam being cut with the dimensions of the profile being off the center of a cutter.

Others that I talk to say that the master must be built using the cutter specified in the drawing.

I say we can subtract half the cutter width and use whatever size end mill we want. In a cam system we could shrink the drawing by a percentage, offset it or something to that matter.

If I am not correct could someone please explain why? The agruement is that the dwells and rises will not be the same without using the exact cutter specified. ]]> Linear and Rotary Motion tds11223 http://www.cnczone.com/forums/showthread.php?t=93029 Advice on how to drive automobile rotisserie http://www.cnczone.com/forums/showthread.php?t=92966&goto=newpost Fri, 06 Nov 2009 21:06:44 GMT Thanks for your time. I am looking to put an... Thanks for your time. I am looking to put an electric motor, preferably 120 VAC, that will allow me to drive the wheel(s) of my restoration rotisserie that supports my '65 Mustang Fastback. Car + rotisserie will weigh around 1400-1500 lbs and will roll on (4) pneumatice tires from a riding lawn mower. I envision a motor acutated by a momentary on/off button and will use a go-kart brake to stop/slow the motion of the rotisserie; in turn, the motor will drive a go kart gear/axle combination.

I am new to the electronic side of the house; I am comfortable around a manual lathe & mill/drill and have decent metal fab skills. In your opinion, what size motor should I be looking for? What type of motor (as I am still learning about stepper vs. servo) will fit this application? I have attached two pics of this application for light civil aviation planes.

Thanks for your time,

NearBeer
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]]> Linear and Rotary Motion nearbeer http://www.cnczone.com/forums/showthread.php?t=92966 IVT Rail System Experience? http://www.cnczone.com/forums/showthread.php?t=92815&goto=newpost Wed, 04 Nov 2009 19:12:24 GMT Hi, I am new to the CNC world and am doing a... Hi,

I am new to the CNC world and am doing a lot of studying right now as I work through my machine design. Was wondering if anyone has used the PBC Integrated V Technology for their linear rails. Seems like an innovative system with the benefit of being integral (in some cases) to the aluminum extrusion. Haven't talked to them about pricing, but it seems like longer runs might be cheaper than some of the alternatives.

Here is a linkl to their site: http://www.pacific-bearing.com/IntegralVTechnology.aspx

Thanks for any thoughts.

Kevin ]]> Linear and Rotary Motion K Allen http://www.cnczone.com/forums/showthread.php?t=92815 Any recommendations for ballscrew oil? http://www.cnczone.com/forums/showthread.php?t=92804&goto=newpost Wed, 04 Nov 2009 16:47:52 GMT Hi, I was wondering if anyone can give a... Hi,

I was wondering if anyone can give a recommendation and a place to buy ballscrew oil. The ballscrews are china made from ebay 25mm x 10mm lead and are being turned at 750RPM, the ballscrews are used to move about 30lbs of weight and just used for positioning so no force will be transmitted back against the ballscrews.

I've been using 10W-30 motor oil, but it seems too thin and tends to fly off the ballscrews spraying everything in sight when the ballscrews get up to speed.

Any suggestions on the proper oil to use in this situation would be greatly appreciated!

Thanks!

FlyingElectron ]]> Linear and Rotary Motion FlyingElectron http://www.cnczone.com/forums/showthread.php?t=92804 Thomson rail length under tension? http://www.cnczone.com/forums/showthread.php?t=92494&goto=newpost Fri, 30 Oct 2009 16:06:00 GMT So, I'm working on a design for a router table, and I've been able to source thomson linear bearings for the three axes cheaply ($5 per each double length bearing). They're in 3/4" size, and the pillow blocks are closed (the rod has to be unsupported to clear the block).

I've also got a different type of bearing with rails for the longest axis. The long axis will have the thomson rails supported by aluminum supports from thomson.. no problem there.

But I'm planning to buy two lengths of 3/4" thomson rail for the X (cross table) axis. This axis would be about 36" across, with the rod maybe 46" and supported on the ends only. I'm going to use two pillow blocks on these rails, for a total of four bearings on this axis, spread over 6 inches linear distance per rail.

My gantry is probably going to weigh about 50 lbs when I'm done, which would make the X axis center flex be something around .1" when done, and that's static, not dynamic load.

So I'm thinking about doubling the end supports, and possibly using the outer support to hold the thomson rod in tension to prevent sag. Something like mounting the outer supports on a sliding plate and using a small jack bolt to place the rod in tension.

Any thoughts on whether/how this would work?

Erik ]]> Linear and Rotary Motion erikjgreen http://www.cnczone.com/forums/showthread.php?t=92494 comercial/home made screw for continuus linear motion? http://www.cnczone.com/forums/showthread.php?t=92448&goto=newpost Thu, 29 Oct 2009 15:19:00 GMT Hi all. I'll make a linear vertical stage, carrying a load of 1 kg max. 0.4 metros of travel probably. This is for an application that would run several hours(10 aprox. ) for a couple of months.

It's possible to find commercial lead screws, nuts and shaft couplers not so expensive, but i ask if a "normal"threaded rod with a "normal" nut could handle this(include the commercial (but inexpensive, $ 20 or so) lead screws and nuts you find over there). The thing is not be changing the screw and the nuts every week because of wear. The velocity could be variable, but maybe an average of 5mm/s, and some 2cm/s peak.

Thanks for any answer. ]]> Linear and Rotary Motion fxs http://www.cnczone.com/forums/showthread.php?t=92448 Resolution http://www.cnczone.com/forums/showthread.php?t=92317&goto=newpost Tue, 27 Oct 2009 20:38:12 GMT Can the same resolution be achieved by using 1.... Can the same resolution be achieved by using
  1. Chain and sprocket,
  2. Timing belt,
  3. Acme screw,
  4. Ground ball screw,
  5. Rolled ball screw,
    Rack & pinion
all other things being equal? I realize that repeatability, efficiency, torque, wear and tare won’t be the same. ]]> Linear and Rotary Motion Allan http://www.cnczone.com/forums/showthread.php?t=92317