New Tormach PCNC440....very dissapointed

I normally don't post much. Really i don't post anything unless i have a problem i cannot solve which does not happen often. I certainly do not go out of my way to talk bad about anyone or a company. I don't have time for that type of stuff. But i feel i need to possibly save someone else some aggravation/disappointment. I bought a brand new PCNC440 as a sort of second op machine to take some pressure off my VMC. I bought it with the power draw bar, tool changer and some tooling. I spent almost 10k. I did not buy their control because i much prefer to use mach3. I have 4 other machines running mach3 daily. I was installing the ATC and thought Tormach would have the drivers/plugin to interface with mach3 since they used to use it. I expected they would not help me. Well, not only would they not help me but they immediately pointed out that i voided the warranty. I really didn't care about the warranty or the electronics, i wanted it with no electronics anyway. The tech that responded was a bit rude in telling me mach 3 was a "bad plan". This really wasn't what i wanted to hear as a customer that just spent almost 10k. Anyway, i got the toolchanger working fine without their zbot board.
I'm running a smooth stepper on this machine because i feel the steppers could use all the help they can get. I'm really not a fan of stepper motors. All my other machines I've installed ac servos. Of course the smooth stepper helped increase the rapids. But the z was a bit slow especially with the power drawbar which probably weighs 10lbs. I figured the motor was just undersized. No big deal. ordered a bigger motor. WELL...in the process of installing the motor, i realized that Tormach had not used a thrust bearing on the ballscrew. That's right folks, no thrust bearing. Hell even an old Bridgeport has a thrust bearing on the leadscrew. So the stepper motor is supporting the whole weight of the head. By this point i'm furious. Pulled out the manual. Sure enough, none of the screws have thrust bearings. Had i know this, i never would have laid out that kind of money for what amounts to a hobby machine. I should have just bought some old junk and rebuilt and retrofit like i always do. Would have ended up with a much nicer machine in the end. (with proper thrust bearings). But i will make it work...because that's what real machinists do.

Wow - you sound like a customer from hell..

Anyway - the 440 iirc uses the steppers as the 'thrust bearings' totally acceptable in this situation IMHO. So if you replace the axis stepper - you need to find one with integrated thrust system - or rework the whole setup.

sam

Somehow this reminds me of an old "Gilligans Island" episode I once watched. In the story line the character with the money forked over a high price for some wax candles. When he took a close look at the candles he'd just bought he noticed that none of them came with wicks. When the buyer asked the seller why there were no wicks in the candles he'd just paid big money for, the seller replied, "Wicks cost extra."

It sounds like you paid big bucks for a candle that didn't come with the customary wicks that used to come with Tormach PCNC's. I can only imagine how frustrating it would be if you didn't have the knowhow to fix these problems yourself.

MetalShavings

A couple of points:
The Tormach website removed all references to providing Mach3 on new machines at least a year ago. In fact, did the 440 ever ship with Mach3?

The PDB and ATC for the 440 were released fairly recently and well after the demise of Mach3.

The lack of thrust bearings sounds a poor design decision. On the other hand, 440 manuals are online so perhaps their careful study is a good idea for a potential purchaser.

I wouldn't expect anything other than a hobby machine for the price of a basic 440. Consider that many people (including me) make commercial use of a 770 or 1100 but most would describe them as hobby or light industrial machines.

There are thrust bearings. They are integrated in the stepper motor. (User adjustable I seems). And as you say - it is in the manual. (Starting on page 156).

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Originally Posted by kstrauss

The lack of thrust bearings sounds a poor design decision. On the other hand, 440 manuals are online so perhaps their careful study is a good idea for a potential purchaser.

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Originally Posted by fast89

i realized that Tormach had not used a thrust bearing on the ballscrew. That's right folks, no thrust bearing.... Sure enough, none of the screws have thrust bearings.

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That is a bad design in my book. Yet another reason to dislike the 440. They cut a lot of corners on this machine to drive the price down. BLDC motor with a under-powered controller. All-in-one Leadshine MX3660, which seems like it was rushed to market. Rolled C7 ball screws.

Only $1800 more gets you the 770, which is a much better design, has much higher rated components, and is much more capable and accurate.

But expecting this machine to work on Mach3 is not a valid complaint. This machine and the ATC were designed for pathpilot. Expecting a USB interfaced ATC to be plug-and-play with Mach3? hmm.

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Originally Posted by fast89

i realized that Tormach had not used a thrust bearing on the ballscrew.

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There are bearings to take the thrust load but they are inside the motor. Conventional design has bearings on the ballscrew shaft and also inside the motor and I've always wondered about that. It seemed to me over constrained and typically some kind of flex coupling is used between motor and shaft to accommodate slight misalignment . For the life of me I could never figure out why the extra bearings and a flexible coupling should be part of the design. Assume that the bearings in the motor are appropriately rated for the radial and axial load that ballscrew will experience and the bearing clearance is adjustable, could someone explain why that is mechanically a poor design?

I do understand the 440 motors might be specials with oversized or angular contact bearings with an adjustment mechanism so they may be more expensive or if you wanted to use your own motors you might not be able too since those bearings and their lack of adjustability could be inappropriate. But that seems to me a marketing issue when people won't buy a machine with custom motors not an engineering design fault

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Originally Posted by fast89

But i will make it work...because that's what real machinists do.

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Personally I don't know what real machinists do or don't do but I do know that sensible people check what they are buying before they do. Seems like your biggest problem, which you have failed to identify, is you didn't do your homework?

Phil

>not a fan of stepper motors
>buys a machine with stepper motors
>complains about stepper motors

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Originally Posted by fast89

I But i will make it work...because that's what real machinists do.

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Speaking as a " real machinist " , Without hesitation I bought a few of these in one shot without physically seeing a tormach before . My choice was based on specs and some of the youtube video's that are available online . The 440 is very a capable machine for it's size and absolutely nothing is comparable within it's price range price . The only complaint I have is the oiler's are junk and they were all broken within a couple months . They were covered and tormach sent me better oiler's from the 1100 i believe . I also considered staying with mach and almost opted out from the tormach pc and pathpilot . But , I wanted plug and play so i bought the computers and I am happy that I did . Pathpilot blows away mach , and I've always been a huge mach fan .

I don't know if they have any true plan of offering a rotary option , and I didn't appreciate the response i got when i asked about connecting my own 4th axis . They were not willing to offer any tech support what so ever , and they also threatened that i would void warranty with any modifications . I hardly consider connecting a couple communication wires to a driver a modification but it is what it is . Rather than doing a "modification " I bought a db splitter which I connected outside the machine . I then connected a bob to one end of the splitter and I have a rotary that runs great without any issues , so it can be done .

As far as cutting goes , these mills are pretty much spot on . They can't be compared to a mori but I don't need that highly capable of a machine either , plus I can cram a lot of these into a shop for the price of a mori . Out of curiosity I connected 3 machines and computers to a single outlet through a 20ft extension cord just to see if it would blow a breaker , it never did .
Great little machines in my opinion