New to CNC and to the forum (TL521ERMP)

[S3MIH3MI]

High I'm new to CNC. I would first like to say, this forum is very informative and I hope to learn as much as I can.

My first post is in regards to the average feed rate and depth of cut on the smaller bench top machines. I realize every machine is different. But I'm just looking for a ball park idea.

For example: I'm cutting aluminum : 1/4" end mill : .005 cut and feedrate is 20 in CamBam. (I believe 20 inches per minute, not sure.)
I may also not be running the spindle fast enough. Acording to the dial for the speed control, its running 4500 but I'm not sure if it's calibrated or just a rough estimate.

I was 1/3 through a 3/4" piece of aluminum and the controller faulted out.
4 flashes on the LEDs. This according to the book is thermal overload. The stepper motors are small pancake like motors driving a larger pully with a belt and the X,Y steppers were a little warn to the touch but not too warm.

It's not the G code. I checked it and started over from the beginning. It got down to where it faulted out and did two more passes then faulted out again in a different spot. Same error code.
The book says to reduce the depth or the feed rate. But I have no reference what it should be.

This is getting a bit long winded, I know but I'm trying to give as much info as I can.

So far I have checked the adjustment for backlash and adjusted the gibs so there is very little drag while operating it by hand. I used a dial indicator to make sure I had no play.

I'm going to give it a rest and let it get back to room temperature, then later tonight I should have some time and I'm thinking of running the same code above the part so it is just the machine and no cutting involved.

Any help would be greatly appreciated.

Thank You

[DrKnow65]

Sorry I can't offer any advise :-(

But I am interested in your findings as I just bought a TL521 as well with all the bells and whistles. Brushless motor, anti backlash screws, R8 spindle, 4th axis ect...

I will see it on Tuesday, but won't have my end mills till later in the week.

Any helpful advise you could relate would be appreciated :-)

P.s. have you added other software other than the Mach3 and CamBam?

[S3MIH3MI]

I just wrote my findings in a new post....
http://www.cnczone.com/forums/genera...se_review.html

But I have found that 5 to 10 ipm are the best speeds and with that I can take as much as .05 for each pass. Another issue was that I had the air compressor on the same circuit and when it started, steppers would actually skip. I have since put the controller on it's own circuit and used an industrial surge suppressor. no more issues for the last week or so.

[Delw]

by looking at your video your biggest problem is NO COOLANT
your second biggest problem is that machine is not rigid
and your 3rd is that a 3/8" endmill for a machine that is not rigid is way too big.

its kinda like using a bicycle to tow a Boat.

use coolant and a smaller endmill

[DrKnow65]

Interesting review, I was under the impression that the TL521 used servo's not steppers?

Delw, you must be a dissatisfied customer? (or one of those holier than thou types?)

I intend to run coolant on mine, but if compressed air is clearing the chips and cooling the bit, isn't that covering the requirements?
I can see the 3/8's EM being at the max of this machines envelope, but isn't that what you do to show the absolute capabilities?
I've never seen anyone show off a high power engine by idling down the street LOL!

[S3MIH3MI]

I don't normally run a 3/8 cutter first off. I just wanted to see how it would cut. It cut fine and yes coolant would be nice but there was 0 heat on both the cutter and the work piece at the feed rate I was going. I usually run 1/4" and smaller. The only reason I did a video was because the ones on youtube did not use the largest cutter it would support.

As far as coolant, this is going to be one of my projects but the machine itself will have to sit in the tank and the "X" axis servo I have concerns about how close it will be to the coolant. If the belt gets coolant on it, there is a good chance it will slip not to mention what it may do to the belt.

[S3MIH3MI]

On a side note. Cutting mild steel with a 1/4 cutter in not an issue. I cut out 2 small cams for a cam shaft. No issue at all. I used manual cooling (Bottle applied) for this as well as carbide instead of HSS.

[S3MIH3MI]

I'm not too concerned about any negative opinions from people that have not tried the machine. I have had 2 machinist, together with almost 60 years in the trade. A bench top mill is just that. You can't expect it to be even close to an industrial machine. It performs well for its size and for what I paid for it, I'm very happy.

Cheers

[Delw]

Originally Posted by DrKnow65 Interesting review, I was under the impression that the TL521 used servo's not steppers? Delw, you must be a dissatisfied customer? (or one of those holier than thou types?) I intend to run coolant on mine, but if compressed air is clearing the chips and cooling the bit, isn't that covering the requirements? I can see the 3/8's EM being at the max of this machines envelope, but isn't that what you do to show the absolute capabilities? I've never seen anyone show off a high power engine by idling down the street LOL!

No just stating facts. 1st alum isnt remotely close to steel, steel you can cut dry or with air, Alum you need lubrication. even using coated endmills on alum you really need coolant.
As far as "absolute capabilities", Your wrong, your basically beating your machine to death by running a endmill to big for the machine. run a smaller end mill and you will have better results.
heres another trick for not so rigid machines and spindles NEVER RUN CARBIDE. run high speed steel endmills. what happens is Carbide is stiff and wont flex or bend, highspeed or tool steel will. so carbide will bounce just like yorus seeing in your video and vibrate and chatter.even with loose bearing or unrigid machines if you put a load on the endmill (NON carbide type) you will get less tool pressure and vibration and your machine wont beat itself to death.

Also with cutting alum if you have a endmill designed for alum you will get 100 times better results and no vibration. I can take my haas and a 3/8 decent brand 2 flute carbide endmill and cut at high speeds but get chatter, I can take 3/8" endmill made specifically for alum and increase the feed rate 3times. from 50 IPM to 150ipm easy and the finish is glass.

however cutting steel I can use any endmill and get a good finish.

Originally Posted by S3MIH3MI On a side note. Cutting mild steel with a 1/4 cutter in not an issue. I cut out 2 small cams for a cam shaft. No issue at all. I used manual cooling (Bottle applied) for this as well as carbide instead of HSS.

exactly cause steel is different than alum and also your using a smaller tool.

Originally Posted by S3MIH3MI I'm not too concerned about any negative opinions from people that have not tried the machine. I have had 2 machinist, together with almost 60 years in the trade. A bench top mill is just that. You can't expect it to be even close to an industrial machine. It performs well for its size and for what I paid for it, I'm very happy. Cheers

your right they preform right with the proper tooling,
S3MIH3MI asked for help he said he was new. I told him the major problems as I saw in his vid.

Delw

[S3MIH3MI]

Thanks Delw
I know you are correct about the cutters and the coolant. I have already been told. LOL
But like I told my brother..... I'm not a machinist. It's learn as I go and if it's close and shiny, I'm happy. LOL

Cheers

[DrKnow65]

Delw, thanks for the informative reply, I much prefer when knowledgeable guys respond with helpful info :-)

A Haas would be a great machine to have, and really in a different league than the TL.
But I wouldn't be able to get it down stairs into my hobby room without making a rather large hole in the kitchen floor to lower it in LOL.

I did the best research I could as far as rigidity in a benchtop mill and thought the TL looked the best in the $2-4K range.
The work area is just smaller than what I really need, so I've got plans to retrofit a larger table, slides, and C3 screws for the x-y.
My biggest concern is software, specifically CAM. I have a full suite of AutoCad 2011 that I've been using for design,
but the pieces I intend to make are heavily profiled 3D and I don't know if LazyCam will handle it...
There are so many CAM options, and my budget is near $0 for at least the next few weeks.

[S3MIH3MI]

DrKnow65

CamBam will do 3D. I haven't cut any 3d yet. But I have the older version of Sketchup and setup a default file with snap set the same as CamBam. I have successfully imported 2 3d drawings and generated tool paths with CamBam. The path looked very good.