TL521ER Purchase/Review.

[S3MIH3MI]

I posted this over at cnczone. I thought it may be of use if anyone was looking for a small cnc in the near future.



After the purchase of the TL mill I read some older post at cnczone of peoples opinions.
Without trying it, they were only opinions but had I read them prier to the purchase I may not have bought the TL CNC mill. So now that I have had the mill for almost 3 months and got used to it, I have an opinion.

I first would like to say that I am not a tool maker by trade but I am an electrician. I have been using a small mill and lathe from Princess Auto for the last 2-1/2 years.

Do to the size of the table there were many limitations and my next machine was going to have a larger table. I decided to go CNC after watching my brother running his.

Let me say that my brother has been a licensed tool maker for over 30 years. He owns a 3 phase CNC with a 48 inch table. I’m not sure what make it is but it has a computer of its own and came from a tool shop.

I had him check out the specs on E-Bay before I purchased it.
Now for my opinion of this bench top CNC.

Price was fair to good
Shipping was ok but they hit me with $400 broker fees
Packaging was very good (2 pieces both in wooded boxes and strapped)
Setup was plug and play (3 hours and I was cutting)
Issues with this machine were minimal and mostly operator influenced.
Speed control only had 2 speeds. Alex sent a new one that day and I had it in a week.
The spindle motor could be of better quality but does the job.
Stepper motors don’t look like much but they are smooth and quiet. I did find out that with these stepper motors, high speed milling is out of the question. They lose too much torque at higher speeds.
Accuracy is as stated on E-Bay. And yes the table is a cast table from China but he claims the ways are hand ground. The full travel is smooth with no tight spots.
The controller is very clean looking and does not even get warm after hours of use. Stepper motors plug in using RJ45 plugs.

To sum it up. My brother was very impressed with the machine. Especially the “Z” axis (3 linear bearings).
He was so impressed he had to bring another tool maker from work to watch it in action. And with the large table, I can use a real milling vice.
All in all, I don’t regret this purchase and would do it again in a heart beat.

I can't compare to any of the other small cnc machines but size does matter.

Here is a short video with a 3/8 end mill.
http://home.cogeco.ca/~fileme/vids/TL5521.wmv

 

[BillC]

Looks good....If I may make a couple of suggestions: The machine is light which necessitates every opportunity to reduce tool induced vibration. The first very prominent source is that the end mill is extended much too far out of the collet - that by its self will induce much vibration. Another way to curtail some of the vibration is to zero the Z axis as close to the work as possible with as little Z axis retract travel (in your program) as needed to clear the work (sometimes 3 - 4 mm is more than adequate). The headstock seems solid but the quill is extended an unnecessary distance. All machines vibrate and some have a harmonic that basically spreads the vibration into assemblies and components that can be destroyed - therefore all methods of reducing vibration should be used as a matter of course in any machines operation. For example: linear bearings are a good example of an undampened assembly that is damaged severely by vibration to the point of destruction.

Try the machine in exactly the same way but make these changes in the set-up and note how much better the machine performs.

Great package...impressive for an 'over the counter' machine - would be an asset in any shop.

BillC

 

[S3MIH3MI]

Thanks.
That was the first time I used a 3/8 end mill on it. I usually use 1/4 and under.
Just wanted to see how it would do.

Here is the same piece but with a 1/4 " cutter.

http://home.cogeco.ca/~fileme/vids/tl521.wmv

 

[lazylathe]

Looks like a great machine!!
A step up from the X2!!!

Andrew

 

[S3MIH3MI]

The first very prominent source is that the end mill is extended much too far out of the collet - that by its self will induce much vibration. Another way to curtail some of the vibration is to zero the Z axis as close to the work as possible with as little Z axis retract travel (in your program) as needed to clear the work (sometimes 3 - 4 mm is more than adequate). The headstock seems solid but the quill is extended an unnecessary distance.

Try the machine in exactly the same way but make these changes in the set-up and note how much better the machine performs.

BillC

Hey Bill. If I need the length on the end mill how can I shorten it? For example. If I needed to cut to full depth in say 3/4" or 1" alum. with a 1/4" cutter. Is there a different way to do it?

I will shorten the retract height. I had it that high because I'm new at this and it was the safe way. I have broke 2 3/16 and 1/8 cutters so far. Do to my programming mistakes. LOL

Thanks
Phil

OK I threw the 3/8 cutter back in and made it as short as possible as well as changed the retract height and speed.
It made a big difference. The plunge was short and sweet and the rest of the cut was as smooth as the 1/4".

http://home.cogeco.ca/~fileme/vids/TL521b.wmv

Thank You very much.

 

[BillC]

Hey Bill. If I need the length on the end mill how can I shorten it? For example. If I needed to cut to full depth in say 3/4" or 1" alum. with a 1/4" cutter. Is there a different way to do it?

I will shorten the retract height. I had it that high because I'm new at this and it was the safe way. I have broke 2 3/16 and 1/8 cutters so far. Do to my programming mistakes. LOL

Thanks
Phil

Not really Phil....unless you roughed to a depth with the end mill 'shoved way in' to the collet then reset it again to do the deep portion. That's not really gaining anything and would be more trouble to stop the program to reset Z and the tool to do the deeper portion. Most std. end mills cut 3 or 4 times their diameter and will cut deeper with some coolant to prevent the shank from galding in the pocket.

Two ways (other than mechanical remedies) to combat tool chatter or vibration is to increase feed or reduce tool speed.

BillC