Re: plasma design 8' x 4'
Hi
Looks fun, are the Y (long travel) motors going to be sprung into mesh or fixed?
If sprung Im not too sure if some bearings running on the bottom face would be a good idea to stop the machine tipping under hard accel / decel.
Keep up the good work
cheers
Mike
www.techservcnc.com
Re: plasma design 8' x 4'
Sprung into rack. I wandered wether bearings running underneath might be needed. Would they "confuse" the sprung tension on the pinion ? if you know what i mean. Mechmate routers do not have the bearings underneath but then their gantry looks pretty heavy.
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Re: plasma design 8' x 4'
Well here it is..
Spent 3 months building this, now ready to plug in.
Will be building a water table to fit under underneath.
Using a plaspak 1a system from candcnc which i managed to pick up on ebay as an uncompleted project.
Now I have the big Mach 3 learning curve to conquer.
Sure hope it all works!
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Re: plasma design 8' x 4'
Re: plasma design 8' x 4'
Looks good mate, well done on getting this far!
I'm liking the sprung tension on the pinion, never seen that before.
Re: plasma design 8' x 4'
That's looking a good 3 month work ads...! When you've got it all tuned up it'll be a nice robust machine.
Just a Q: What are the Vbearings running on on X and Y? It is the proper machined rail, or have you found some alternative (angle iron, or something)? And did you use eccentric bushes to pull the bearings onto the rails, or some other method? Just curious because my next machine will probably be using v bearings.
Anyway, looking good!
Re: plasma design 8' x 4'
X is running on home ground rail (an angle grinder on a skate) check out Mechmate forum they build some fantastic routers.
Y is running proper ground rail.
yep, used v bearings on eccentric bushes from superior bearings in USA.
Had motors running today, 80% satisfied. Running out of time now as I wont be allow to play with over Christmas!
Re: plasma design 8' x 4'
Quote:
Originally Posted by
adscnc
X is running on home ground rail (an angle grinder on a skate) check out Mechmate forum they build some fantastic routers.
Y is running proper ground rail.
yep, used v bearings on eccentric bushes from superior bearings in USA.
Had motors running today, 80% satisfied. Running out of time now as I wont be allow to play with over Christmas!
christmas is past!!!:naughty:
how is your build going i am hoping to build same sized plasma/router but racks etc to expensive,thinking about belt drive(see my linear drive thread)
where did you buy racks etc and how much if its not to cheeky to ask???
:beer:Tom
Re: plasma design 8' x 4'
Cutting metal now. Big learning curve here!
Have already sold some cut plates off the machine.
The x axis rails are ground angle iron, have a look at the mechmate for info on this. Don't dismiss the idea as mad and bound to be inaccurate! Have a look at what the lads build on the mechmate.com. The Y rails are no2 ground v rail from Eurobearings. The V rails from superior bearing in USA. The geared racks from WMH bearings Tamworth.
Al
Quote:
Originally Posted by
dickieto
christmas is past!!!:naughty:
how is your build going i am hoping to build same sized plasma/router but racks etc to expensive,thinking about belt drive(see my linear drive thread)
where did you buy racks etc and how much if its not to cheeky to ask???
:beer:Tom
Re: plasma design 8' x 4'
Quote:
Originally Posted by
adscnc
sorry larger pics here..
Hi Ads,
Great pics, thanks for sharing.
I have a couple of questions, I am genuinely interested. Having worked hard on getting rack and pinion / V bearings right, why did you decide to switch to Ballscrew / linear guide for the Z axis?
Also on the X carriage, the ratio of the distance between the wheels left/right to front/back is high. i.e. Its a wide, short carriage. In the past I have had problems with linear rails that stick when the ratio is too high, like the runners in a chest of drawers. Have you ever had anything like this? (probably not a problem because you drive from both sides)
Lastly, what kind of spring tension do you use on the rack? Ever seen it jump?
Best wishes
Dave
Re: plasma design 8' x 4'
Quote:
Originally Posted by
Speedave
...
I have a couple of questions, I am genuinely interested. Having worked hard on getting rack and pinion / V bearings right, why did you decide to switch to Ballscrew / linear guide for the Z axis?
Also on the X carriage, the ratio of the distance between the wheels left/right to front/back is high. i.e. Its a wide, short carriage. In the past I have had problems with linear rails that stick when the ratio is too high, like the runners in a chest of drawers. Have you ever had anything like this? (probably not a problem because you drive from both sides)
..
There is a rule, known as the 2 to 1 rule, which says that the point at which force is applied should never be further away than twice the distance between the support bearings. So if your bearings are 50mm apart the maximum height of your workpiece is 100mm (assuming the top of the gantry is not constrained). See the video here (if it asks you to register just put in any old rubbish for name and email, it doesnt check). A similar rule applies horizontally, but where both sides are running on rails and the two sides are connected its 4:1 or more depending on rigidity of the connecting piece, so for bearings 50mm apart the maxmimum width between rails is typically around 200 - 250mm. If you look for example at the Igus dryLin carriage plates, they always stick to a ratio between 3 and 4:1
Re: plasma design 8' x 4'
How about that? that video is excellent.
So the next question is what is the ratio in Ads' machine.
