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Surface grinding?
« on: May 13, 2008, 05:51:37 PM »
I'm pretty new at CNC and have been using Sheetcam and Mach3 for our router (fairly successfully after a couple of frustrating months)... and plan to get a CNC surface grinder later on this summer.....

I can't seem to find any info or indication that I can use Mach3 for surface grinding. Is this the case? I'll need other controller software? Any suggestions/recommendations?

-- Rich --
Re: Surface grinding?
« Reply #1 on: May 14, 2008, 08:21:46 AM »
From what people have told me, compensating for the wheel wear isn't an issue as there's some code you can insert which makes the wheel shunt aside to be automatically dressed and recalibrated.

The machine at the top of my consideration list is the Syil U2 http://www.syilamerica.com/product_u2.asp which is the least expensive and smallest CNC surface grinder I could find. The maker says that it's compatible with many software packages though acknowledges that the ones to run it in the surface grinding configuration need to be totally 3D.

Any shop I've asked only have and know about humongous machines.

We plan to be doing only ONE type of job on this machine: making reeds. The blanks are spring steel Rc55, about 1.5" x 5" x .025" thick, and need to have a shape ground from them that leaves them looking like a knife blade - but not a uniform taper. A reed's taper is slightly S-shaped going from one side at .025" arcing down to about .015" then a much larger arc to decrease the blank to about .008" then a straight portion slowly tapering down to about .005" and then another large arc to the end of the other end of the blank, ending about .003".

Historically they used some sort of pantographing surface grinder for this. My problem is that I don't want to spend forever doing trial/error to get the shape "right". We'll - it wouldn't be forever if I only had one profile to get right, but I have 44 profiles for each set of reeds and all the profiles need to be smoothly "related" it's neighbor in shape. I'm currently working on a spreadsheet to interrelate all the dimensions automatically such that after I cut one and test it, I can hand file it to adjust it and enter the new dimensions into the spreadsheet which will repopulate all the dimensions again for the next round of testing.

Other people have suggested that I get a small grinder and have it converted to CNC but I haven't been able to find anyone who does that sort of thing. And when we talk "small", I mean that the largest working area we'd need is 2"x6". Plus we don't want a large machine as our shop space is very limited.

-- Rich --
Re: Surface grinding?
« Reply #2 on: May 14, 2008, 12:15:22 PM »
I suggest you get a small milling machine and add a grinding spindle.

To do this you would need very good dust collection or the machine will soon be ruined.

There are lots of various sized mills available and fitting a grinding attachment would be minimal compared to converting a Surface Grinder.

Plus you will have the advantage of being able to do milling on it.  ;D

Ebay or this forums bargain basement would be places to start looking.

HTH
Phil_H
The Good Thing About Mach3, Is It's very Configurable

The Bad Thing About Mach3, Is It's Too Configurable
Re: Surface grinding?
« Reply #3 on: May 14, 2008, 02:14:00 PM »
There are lots of various sized mills available and fitting a grinding attachment would be minimal compared to converting a Surface Grinder.
I've looked around quite a bit and haven't found any small mills that can surface grind Rc55 springsteel to +/- .0002" tolerance over 5". Besides, everyone I've talked to says that mills don't that the correct speeds and bearings to do surface grinding. So far the Syil U2 seems to be the only thing I've found. I'm also not a machinist and don't know the first thing about choosing machinery or fitting and adjusting them.
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Plus you will have the advantage of being able to do milling on it.
I have a CNC routher now that I'm able to do all my milling on.
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Ebay or this forums bargain basement would be places to start looking.
Done that but can't find anything suitable. Other suggestions of places look? Really - I've looked hard and called many places that sell machinery and have had very little luck.

-- Rich --

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Re: Surface grinding?
« Reply #4 on: May 14, 2008, 11:56:43 PM »
Maybe try to get in touch with Keithorr (Ed) and he might be able to point you in the right direction.
http://www.machsupport.com/forum/index.php/topic,6024.0.html
http://www.keithorrblowpipes.com/contact.htm
"CONFIDENCE: it's the feeling you experience before you fully understand the situation."
Re: Surface grinding?
« Reply #5 on: May 15, 2008, 05:13:56 AM »
The machine at the top of my consideration list is the Syil U2 http://www.syilamerica.com/product_u2.asp which is the least expensive and smallest CNC surface grinder I could find. The maker says that it's compatible with many software packages though acknowledges that the ones to run it in the surface grinding configuration need to be totally 3D.

The machine at the top of your list is a milling machine ??????????

I've looked around quite a bit and haven't found any small mills that can surface grind Rc55 springsteel to +/- .0002" tolerance over 5". Besides, everyone I've talked to says that mills don't that the correct speeds and bearings to do surface grinding.
-- Rich --

Correct a milling machine spindle would not be suitable for grinding. But did you notice i said use a GRINDING SPINDLE which guess what, is suitable for grinding.

I am an engineer, i looked at that machine and had to laugh at the coolant nozzle when used for grinding the coolant tank would be empty in no time and the coolant would be on the floor, up the walls, all over the place.  ;D ;D ;D

There are no guards around the table to keep the coolant in check.

As you may not know you cannot do milling on a router the bigger the router the less accuracy due to flexing.

On my own milling machine i milled a 12.5 mm slot x 165mm long the length of an aluminium billet i made 50 items the tolerance i achieved was .005mm max


Phil_H
The Good Thing About Mach3, Is It's very Configurable

The Bad Thing About Mach3, Is It's Too Configurable
Re: Surface grinding?
« Reply #6 on: May 15, 2008, 08:26:53 AM »
Think you need something just a little bit bigger than what your considering.
Why? The only thing we'll be doing with the machine is grinding springsteel max of 5" long.
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MSG and Enco sell a bench top surface grinder. They could be CNC'd completely ie; controller, stepper, PC, Mach software, etc. and you would be ahead of the game.
I couldn't find dimensions for the MSG but the 3 foot (plus travel?) Enco is far too large for our shop space.
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I believe that MACH can run a surface grinder nicely, but some G-Code creation to address the operation of surface grinding will be in order.
I'm glad that Mach can do it and I realize that I need to find some g-code software. I'm currently using Sheetcam which I really like but isn't applicable for SG work. Any suggestions on software to convert CAD to g-code?
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Remember that you grind / remove material at .0001 to .00025" with a small surface grinding machine. Grinding to tolerance is similar but a different operation than say milling a piece. There are books written on grinding and the proper application of grinding wheels to different materials not to mention sites like Norton and others on the internet.
I don't "remember" anything as I'm new to machining. ".0001 to .00025" sounds just fine by me... and I really appreciate pointers to places like Norton (never heard of them before). Thanks, I'll check them out. Please feel free to "mention" more! I need the help!

 
Re: Surface grinding?
« Reply #7 on: May 15, 2008, 08:28:49 AM »
Maybe try to get in touch with Keithorr (Ed) and he might be able to point you in the right direction.
http://www.machsupport.com/forum/index.php/topic,6024.0.html
http://www.keithorrblowpipes.com/contact.htm
Thanks for the links! I've just e-mailed to Keithorr and copied the stuff on that forum topic (even if I don't understand it it may come in handy at some point).

-- Rich --
Re: Surface grinding?
« Reply #8 on: May 15, 2008, 08:39:33 AM »
The machine at the top of your list is a milling machine ??????????
Yes but that's the only small CNC I can find that does SG. Probably not well? I don't know as I'm not a machinist and don't know my way around here. If someone would come up with a small CNC SG I'll buy it. Or if someone would convert a small SG to CNC I'll buy it. Any suggestions/leads?
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I am an engineer, i looked at that machine and had to laugh at the coolant nozzle when used for grinding the coolant tank would be empty in no time and the coolant would be on the floor, up the walls, all over the place.  ;D ;D ;D

There are no guards around the table to keep the coolant in check.
Thanks for the input - I had no clue.
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As you may not know you cannot do milling on a router the bigger the router the less accuracy due to flexing.
I don't know. That U2 seemed pretty small and heavy-duty though. But as I say... I don't know. I do know that I'll never need to grind anything over 5" long (which is pretty small?)
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On my own milling machine i milled a 12.5 mm slot x 165mm long the length of an aluminium billet i made 50 items the tolerance i achieved was .005mm max
The stuff we need to do is grind springsteel 5" long with less than .0002" over that length... and we need to make thousands of them.

-- Rich --

vmax549

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Re: Surface grinding?
« Reply #9 on: May 15, 2008, 12:36:05 PM »
Rich you may want to check on geting the reeds subed out to a grinding shop that has the right equipment to do that type of grinding. First of all trying to do micron work at the low end level is NOT easy or cheap. It take very high end grinders to maintain that accuracy day in and day out. And for the most part they are NOT small for a reason(;-) If you are really needing .0002 tolerance then you will have to WORK in the .00002 range. NOT an easy task. I can lean on my bridgeport and see more error than that. The difference from a cold machine to a warm machine is way more than that as well.  Just trying to hold something inside of that error can be a challenge in itself.

Hope that helps  (;-) TP