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  #1  
Old Fri 05 October 2012, 07:53
SOSx
Just call me: SOSx
 
Devon
United Kingdom
Feed rates for Cable porter 6902 type 5?

Hi All,

We recently purchased a used (More like never got working properly) MM
4ftx4ft machine. The base structure has been done really badly and has needed a lot of extra cross bracing to stop it rocking like jelly in an earthquake every time the gantry changed direction. Any way we have pretty much addressed that and are now completely re-wiring the electronic at the moment (they were about as competently fitted as the base was built!).

Right I'll get to the point - This machine came fitted with a 110v cable porter 9602 type 5 router (fed by site inverter from 230v uk mains) yesterday afternoon we set up a program to do a few test cuts to see what accuracy was like. We did some calculations for feed rate based on the 23000rpm with a 6mm twin flute down cutter. We have not fitted any speed control for the router yet but the calculator we use said that about the lowest feed rate we could manage keeping the chip load acceptable was about 100inch/min (98 to be precise). Anyway the router after about 4 inches of cutting a 6mm deep pass in birch plywood got completely bogged down to the point that the tool stopped and got stuck in the timber.

Another thing is that the collet is quite warn out. It appears to be a 6mm collet but I can only find 1/4 inch or 1/2 inch ones online (a 1/4 inch tool doesn't fit). Does anybody know if you can get replacement collets in the UK or Europe, my searches have led to nothing outside of the US?

I'm desperate to get this thing cutting but i'm worried we simply wont be able to run it at a speed and depth to keep the chip load acceptable with out the motor bogging down? Any suggestions?
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  #2  
Old Fri 05 October 2012, 08:22
digit
Just call me: Dominic
 
Quebec
Canada
Are you sure that your router keep 23,000 RPM under load without slowing down ?
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  #3  
Old Fri 05 October 2012, 08:28
SOSx
Just call me: SOSx
 
Devon
United Kingdom
I'm Sure it doesn't! Infact under load in this situation it stalled completely!!
The feed rate was actually about as slow as we could run while maintaining a just about acceptable chip load for 23000rpm so if slowed to say 18000rpm under load the chip load would have been ok?

Does anybody have this router? What sort of feed rate and cut depths are you running and at what rpm (if speed controlled).
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  #4  
Old Fri 05 October 2012, 11:06
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
Do you mean the 6902? It is only 1 3/4 HP

http://www.facebook.com/notes/review...52104484898042
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  #5  
Old Fri 05 October 2012, 11:29
timberlinemd
Just call me: Steve #66
 
Arizona
United States of America
Actually, at 110v this 10amp motor would do little more than 1hp at best. (1HP=746 watts, but some wattage is lost as heat, so I use 900/1000 watts = 1HP)
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  #6  
Old Fri 05 October 2012, 12:33
SOSx
Just call me: SOSx
 
Devon
United Kingdom
Hi Mike, Yes the 6902 as in the title not 9602 as in the post.

Timberlinemd - I do realise that it is a arelatively low power unit but the feed rate and depth of cut are quite low! I would expect a lot more from a Descent spindle (we have a decent 2.2KW Perske on our other machine). But this is what the machine came with
and I was hoping it would be able to do a little work at least before having to replace it with a new spindle?
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  #7  
Old Fri 05 October 2012, 18:15
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Spindles and routers are two different animals. I started out with a 3-1/4 hp router on my Shopbot and was very disappointed. After changing to a 3 hp spindle, things improved dramatically. The spindle handled the expected load. The router did not.

I credit the problem to advertising. Router manufacturers seem to be immune from any "truth in advertising". Spindle manufacturers seem to abide by the rules.

My 3-1/4 hp router acted much more like it had a 1-1/2 hp motor than like it had a 3-1/4 hp motor.
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  #8  
Old Sat 06 October 2012, 02:09
SOSx
Just call me: SOSx
 
Devon
United Kingdom
Hi Richards- i do realise the differences between spindles and routers and do intend to put a spindle as and when it is possible. BUT! At the moment i cant afford to do that and was hoping/expecting for the machine to at least be able to process a few jobs first (making the money for a spindle).

I haven't heard from any router users yet (and I believe that there are quite a few)?? Are there any people using these routers or equivalents?? What feed speeds/depth of cut are you achieving.

PLease no replies from people just telling me I need to get a spindle as I dont have the cash to do that at the moment!! and need to get some cuts out of this.
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  #9  
Old Sat 06 October 2012, 03:48
KenC
Just call me: Ken
 
Klang
Malaysia
Why don't you show us your list.

I'm one of those who can't afford to buy a router an than "upgrade" to a spindle later on, I just went spindle from the beginning...
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  #10  
Old Sat 06 October 2012, 03:58
SOSx
Just call me: SOSx
 
Devon
United Kingdom
Ken - what do you mean by list? Do you mean our speed and depth calculations?

This machine (second hand) came with this router already fitted.
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  #11  
Old Sat 06 October 2012, 04:30
KenC
Just call me: Ken
 
Klang
Malaysia
I meant a list that contain tabulated numbers with bit size, bit type, rpm, feedrate, depth of cut, type of material, & type of wood... etc
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  #12  
Old Sat 06 October 2012, 04:32
KenC
Just call me: Ken
 
Klang
Malaysia
I presume you don't own a MM.
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  #13  
Old Sat 06 October 2012, 04:39
Surfcnc
Just call me: Ross #74
 
Queensland
Australia
Hi SOSx

You sound concerned about using the router but there really is no need.
Use your ears and just like hand held routing you soon know if you are overfeeding.
Black burnt edges is of course from going far too slow, you see that one all the time on handheld router jobs and occasionally on CNC work too

Nice to hear you have sorted out the Mechmate machine and given it a fresh start with some new needed mods.
Send us some pics of your new machine once you get it going.

Regards
Ross
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  #14  
Old Sat 06 October 2012, 05:08
KenC
Just call me: Ken
 
Klang
Malaysia
It doesn't matter if you own an MM, all I need is to access your cutting experience.
End of the day, all setting figures are not cast in stone.
In fact, spindle owner can give better advise on speed & feed... because we actually know it
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  #15  
Old Sat 06 October 2012, 07:26
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Just watch the "chip load". Set the feed, speed and depth of cut so that you get the desired chipload without bogging down the router or the stepper motors.

When I cut solid wood, I used a chipload of about 0.015". When I cut composites, I used a chipload of about 0.025". Experiment to see the maximum chipload that leaves the desired finish. Too small a chipload and you'll burn up cutters. Too great a chipload and you'll do a lot of sanding.

With a 3-1/4 hp router, I took shallow cuts (about 1/4th inch or less) in solid wood (depending on the diameter of the cutter, which was usually 3/8").

Chipload = (Feed Speed in inches per minute) / ( RPM X Number of flutes)

RPM = (Feed Speed in inches per minute) / (Chipload X Number of flutes)

Feed Speed = RPM X Chipload X Number of flutes

300" per minute / (15,000 RPM X 2 flutes) = 0.01"

300" per minute / (15,000 RPM X 1 flute) = 0.02"

With my router, I normally used a 1-flute cutter.

If your router has variable speed, try cutting in the 12,000 to 15,000 RPM range.

Make multiple passes to get to full depth and then make a full depth climb cut "finishing" pass that removes about 0.02" to 0.05" to remove the ridge lines.

As Ross said, just use your ears and your eyes. A CNC machine is just a tool. Learn its capabilities and it will serve you well.

Last edited by Richards; Sat 06 October 2012 at 07:37..
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  #16  
Old Sat 06 October 2012, 13:00
SOSx
Just call me: SOSx
 
Devon
United Kingdom
Hi Ken / Richard,

We did our chip load calculations using g-wizard (as we normally do with our other "Perske spindled" CNC). The speed feed and plung rates effectively equated to pretty much the minimum chip load the tool could manage. Much slower and we would just start burning up tools. I dont have the paramenter to hand but will put them up tomorrow when I go back to the workshop.

As for the machine other than the router worry I am happy with the purchase.
The base was severely under built and has needed a large amount of cross bracing to give some ridgidity. And as i said the wiring was also extremly badly installed.
But it is getting there now. This afternoon my business partner Matt has been re-wiring the control box with the new ethernet control card, Smooth stepper, all in one pc, solid state relays etc. I have machined (on our other cnc machine) a birch ply shroud/surround for the touch screen and mounted onto the control box. I have also just about finshed caming a new base board + vac bed for it which I will cut on the MM (if i'm able to get a decent cut from router). I will get some pics up tomorrow.

We actually already have work backing up now that we could really do with cutting on the MM and its frustrating me that we have already spent a week working on the machine and have not got a decent cut out of it yet.
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  #17  
Old Sun 07 October 2012, 21:35
Regnar
Just call me: Russell #69
 
Mobile, Alabama
United States of America
Quote:
Originally Posted by SOSx View Post
We actually already have work backing up now that we could really do with cutting on the MM and its frustrating me that we have already spent a week working on the machine and have not got a decent cut out of it yet.
So essentially this is costing you money and you still have a crappy router? If the machine cant cut it cant make money.

But back to the problem at hand. Have you checked the routers brushes? They might not be making full contact and your looseing power. Might also have dust inside which could also effect the amount of power.

Also you might want to check your chipload calculator again. My numbers say your cutting around .002 or about 5 times to small. Gwizard confirms you will be rubbing and gives a warning. By my calculations at your fixed RMP you should start at 460ipm and increase until you dont have a good cut quality. Hp should only effect how deep you are able to cut.
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  #18  
Old Sun 07 October 2012, 22:01
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Hey Russell what is that Gwizard program you are referring to?
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  #19  
Old Sun 07 October 2012, 22:05
KenC
Just call me: Ken
 
Klang
Malaysia
You bought a non-running MM?
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  #20  
Old Mon 08 October 2012, 09:13
Regnar
Just call me: Russell #69
 
Mobile, Alabama
United States of America
Heath the G-Wizard is a Speed and Feed Calculator that takes in account for chatter/tool deflection and a few other variables. I feel the program is geared more towards CNC Machinist rather than wood workers but he did include a few wood species in his drop downs.

http://www.cnccookbook.com/CCGWizard...CSoftware.html



I also recommend reading some of the articles on his blog as they are very informative.
For example this one. http://blog.cnccookbook.com/2012/03/...tting-success/
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  #21  
Old Tue 09 October 2012, 03:52
Robert M
Just call me: Robert
 
Lac-Brome, Qc
Canada
Send a message via Yahoo to Robert M Send a message via Skype™ to Robert M
Thanks Russell for these valuable links. UsefulůVery useful !
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