MadModder
Gallery, Projects and General => Gallery => Topic started by: John Stevenson on September 24, 2010, 06:12:13 PM
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Been working with Art Fenerty of Mach3 fame on his new gear-cutting program.
Basically brought about because he wanted to do clock gears and then it got all out of hand with eccentric gears and all that artistic crap.
Link to the site at www.gearotic.com (http://www.gearotic.com) there is a demo copy but the tutorials are worth watching.
Anyway I wanted to get the program back to making mechanically perfect gears and bring in some ideas. Most of the cutting is for routers making thin gears with a vertical spindle but there is an option for doing spur and helicals travelling across the face.
Now for the good bit even though CNC is needed the gears are cut with a conventional off the shelf $3 end mill and that end mill will cut any gear provided it can reach the root, don't believe it, watch the video.......
http://www.youtube.com/watch?v=qZJ95I3ZWro (http://www.youtube.com/watch?v=qZJ95I3ZWro)
Not a great picture, the white nylon doesn't help but I'll redo it later on brass or similar. Main thing is it shows the operation, the cutter blocks a slot out and then by using all 4 axis at the same time it moves away, raises the cutter and rotates the 4th axis so each pass is at a different angle and part of the involute. You have the choice of selecting how many passes per tooth.
But because specials cutters are not needed it's now very easy to modify gears to fit an application. I cut two 14 tooth gears to text book specs, mounted then on two pins the required distance apart and they ran perfectly, I then made two more identical blanks but cut 13 on one and 15 on the other.
(http://www.stevenson-engineers.co.uk/files/gear_cluster2.jpg)
You can swap these in any order and they run fine. Helicals are still a work in progress, they work but the tooth shape is not correct yet.
(http://www.stevenson-engineers.co.uk/files/helical_2.jpg)
Again simple tooling, in most of these cases the tool was a throw away FC3 3mm end mill costing £2.99
John S.
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Bloody incredible - I lost your thread a bit - you mentioned clock wheels , so does it still do clock wheels? All the messing around I went through trying to make the correct module cutter or purchase a commercial one at £65 !! - so your sayng any module wheel could be cutting using an endmill?
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Bloody incredible - I lost your thread a bit - you mentioned clock wheels , so does it still do clock wheels? All the messing around I went through trying to make the correct module cutter or purchase a commercial one at £65 !! - so your sayng any module wheel could be cutting using an endmill?
Craynerd: I think you missed the bit that said "by using all 4 axis at the same time", your £65 cutter will look like a Billy Bargain by the time you've paid to convert your X2 to 4 axis CNC. £65 won't even buy you a copy of Mach 3. (The cutter will still be faster btw).
Good stuff though John, if only I had CNC on my mill (or better still another mill that was CNC). Have you tried cutting steel? I've never had much success with tiny end mills - they usually 'blow up'. :(
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John,
Is there any faceting of the tooth surface?
Bernd
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Setup and did a 2.5Mod 11 tooth 45 degree helical today.
(http://www.stevenson-engineers.co.uk/files/helical_new.jpg)
Came out perfect, checked it on the gear verniers and it was within two thou of where it should be.
51 minutes with a 3mm end mill running at 500mm/min - proof.
(http://www.stevenson-engineers.co.uk/files/helical%20screen.jpg)
Elapsed time is next to the EStop button
Video here http://www.youtube.com/watch?v=OI8f6Lrwx00 (http://www.youtube.com/watch?v=OI8f6Lrwx00)
Watch from 2.08 until 3.01 and you will see how it steps over in the Y and the 4th axis follows it to form the involute in a series of discrete steps.
You can choose how many passes it makes to facett the flanks, default is 10 but I'm running lower for testing to trade speed for quality although even at 8 they are coming out very well,
Shout up if I'm boring you playing to an audience of one.
John S.
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Were do you find the time :coffee:
Totally fascinating John, :coffee: not that I can see myself ever doing it though ... not :smart: enough :thumbup:
I can see this becoming the way for those with 4 axis cnc set-ups and a few wanting to add the 4th ..
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and don't say "on my wrist" :doh:
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I'm watching:o) Very Cool!!!
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I too am watching with great interest, thinking of when I get my CNC conversion done and then get my rotab converted (or my ER32 spindex converted as well)
Looks like really good software, I may well get it when I get CNC'ing properly.
Tim
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Setup and did a 2.5Mod 11 tooth 45 degree helical today.
. . . .
Shout up if I'm boring you playing to an audience of one.
John S.
Hi John
Don't know how many people are posting but I am sure that you can add a few zeroes behind that audience of one. Very interesting, thanks for showing it to us. :doh:
While there may not be a lot of people that use this right away, I am sure that a few will be starting to plan to CNC their lathe and mills so that they can machine parts like this. :D
Cheers :beer:
Don
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Shout up if I'm boring you playing to an audience of one.
John S.
The last time we Colonials seriously listened to any of you blue-faced throwbacks was when Winnie gave his "Iron Curtain" speech in Missouri? While Winston was a master of the theatric use of the English language, able to send chills down the back of even second-language English speakers and capable of playing the audience even when there wasn't one, he never achieved the gritty penetration of reality that you do on a regular basis.
That's fabulous work in any language. Your contributions here and elsewhere in the electromagnetic domain are a national treasure. Apply (or whatever one does) for an OBE, etc.. Lizzie II knighted some braindead beetle - she should be able whack her sword on you.
Keep at it, John. You're a credit to the race. I'll defer discussion of which race until a future time.
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John,
Very very interesting - I have the CNC machine (having converted a BF20 slowly over the last year or so) but which currently lacks ball screws to give it the level of accuracy required for cutting gears in this fashion. However the screws are on order and the next stage of the conversion is nigh - in theory anyway.
Since my next grand project is a skeleton clock, my next question is 'when will the programme be available', 'how much' and what else will I need' (I currently run Mach 3 with 4 axis configured).
Deeply impressed - but not surprised having read much of your work here and having used Mach 3 for a year or so.
Simon
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Hi Simon,
Available today @ $75
Regards,
Hamilton
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Heya John,
Count me in as one reading this with great interest. Just a slow poster!
Eric
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John that is fantastic. I have seen gears done on commercial CNC equipment that didn't do as well as that plus you cut it dry so we could see what was going on. Keep it up, I don't have CNC at my home shop yet but its in the plans.
Regards,
Gerald.
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Wow, totally cool. Now that I have a 4th axis, I would love to try cutting some gears, something that I wouldn't have thought about 6 months ago. Just can't justify the price just to try...
Care to post a helical gear, 4th axis code file for me to try? All I can offer is a few pics of the results...
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Yup give us a clue on what you can handle. size of cutters available, speeds feeds etc.
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Hi John, how about the same code used to cut the helical gear in the video posted? I can handle something that size and at the same speed.
Thanks! :thumbup:
Paul
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Just can't justify the price just to try...
Would I be right in thinking you're worried about trashing such a large piece of metal and/or cutters? If so, why not try some machinable wax first? You can cast up as big a lump as you care to try, and if you make a bad cut or you break the wax - well, you can just melt it down & start again. The wax will break long before the tool, so crashes aren't a problem (well, so long as the crash isn't so bad it hits the dividing head and/or table...)
Best thing is, even if you buy it (rather than roll your own), it's cheaper than metal and re-usable.
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Actually, I was talking about the price to try the gear creation software, not the material or tools.
I've heard of that machinable wax before, but never tired it. My 'machinable wax' is leftover scraps of HDPE plastic, of which I have much more than I'll ever use. I wish there was a way to melt the huge amount of chips created back into solid bar....
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.....I wish there was a way to melt the huge amount of chips created back into solid bar....
have a look at AdeV's thread on machineable wax (http://madmodder.net/index.php?topic=2729.msg29059#msg29059) including melting thereof ....
Dave
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Hi John, how about the same code used to cut the helical gear in the video posted? I can handle something that size and at the same speed.
Thanks! :thumbup:
Paul
OK will do, one last question, what side of the table, viewed from the front is your 4th axis, code is relative to this position.
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...code is relative to this position.
Right. :loco: I mount my rotary table parallel with the x axis, and it's usually on the +X or right hand side.
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One more program to design gears is Solutions ! http://delphusa.com/index.htm (http://delphusa.com/index.htm)
When I get back into my long term clock project, I'll spend a bit of time comparing the two. All I need is the 2D DXF files.
http://www.ldrider.ca/cnc/garysclock/garysclock.htm (http://www.ldrider.ca/cnc/garysclock/garysclock.htm)