Intermittent Pallet Pool Hydraulic Problem

[Orange Vise]

One of our DMG Mori HMCs has a pallet pool that works entirely with hydraulics. The APC is simple with the following functionality:

1. Index to any pallet position
2. Tilt up/down
3. Extend/retract

We're having an intermittent issue where the unit is pausing while tilting down in the extended position after moving a pallet. This happens immediately after the pallet makes contact with the rack and the APC is unweighted.

You can hear the hydraulic pump cycling continuously trying to maintain pressure (pressure keeps dropping). Eventually it times out and I have to recover manually. Hydraulic pressure stops dropping at this point.

Recovery is easy. Most of the time I simply tilt-down all the way, retract, and clear the errors in the control. Sometimes I have to tilt up first, then tilt back down, and retract. I'm guessing the hydraulic cylinder is binding and needs to be replaced. Simple enough if that's the case.

Am I missing anything? I'd imagine this pallet pool design is not unique to DMG Mori.

Thanks.

 

[Houdini]

Movement reference ?

 

[Houdini]

Sounds like it to me also, man is this the same hydraulic BS machine you have been having issues with that manifold?
Surprised you bough DMG macheen's after being on here for a minute

Price vs performance surprised you didn't buy Mazak or DN.
Haas would be good for the ROI, but their HMC pallet pools errors out to much, like a DMG apparently

Would be nice to have a graphic interface with pressure sensors at every orifice(he said orifice )
that way you could quickly diagnose pressure issues without having to interface between connections with pressure sensors for testing shit.

Only other thing I could think of as simple is a rubbing area that has created a hang up spot, like a burr or shelf.

and the standard obvious bullshit of solenoids or manifolds or seals causing issue.

I hate hydraulic issues, even my new saw is mostly linear rails, and servo motors and ball screws now, don't know which is worse though

 

[Garwood]

One of our DMG Mori HMCs has a pallet pool that works entirely with hydraulics. The APC is simple with the following functionality:

1. Index to any pallet position
2. Tilt up/down
3. Extend/retract

We're having an intermittent issue where the unit is pausing while tilting down in the extended position after moving a pallet. This happens immediately after the pallet makes contact with the rack and the APC is unweighted.

You can hear the hydraulic pump cycling continuously trying to maintain pressure (pressure keeps dropping). Eventually it times out and I have to recover manually. Hydraulic pressure stops dropping at this point.

Recovery is easy. Most of the time I simply tilt-down all the way, retract, and clear the errors in the control. Sometimes I have to tilt up first, then tilt back down, and retract. I'm guessing the hydraulic cylinder is binding and needs to be replaced. Simple enough if that's the case.

Am I missing anything? I'd imagine this pallet pool design is not unique to DMG Mori.

Thanks.

Install a pressure gauge on each side of the hydraulic cylinder so you can watch what's going on.

Something I've seen before (very similar problem) was a new machine installed and the techs hooked up the hoses wrong on first start. a cylinder would randomly lose pressure/control during operation. Pressure gauge showed that what was happening was the cylinder was occasionally getting pressure to both ports at the same time- The valve was messed up. New manifold valve and the problem was fixed. Theory is somehow the hose mix up damaged the vale, but we'll never know.

 

[boosted]

I did service on one of the RPP's several years ago that had a similar issue.

It had a prox switch that was triggering intermittently, and would sometimes just time out because it never completed received the position signal it was waiting for. I don't recall the hydraulics hammering away, but it was so noisy in there that it would have been hard to tell.

It's pretty easy to crawl under there and watch the switches light up (from a safe distance) if you haven't tried that already.

 

[boosted]

Sounds like it to me also, man is this the same hydraulic BS machine you have been having issues with that manifold?
Surprised you bough DMG macheen's after being on here for a minute

Price vs performance surprised you didn't buy Mazak or DN.
Haas would be good for the ROI, but their HMC pallet pools errors out to much, like a DMG apparently

IMHO this impression is why folks need to be careful about the echo chamber that forms in places like this.

The NHX4000 and NHX5000 are far from perfect, but on paper they outperform a similar Makino for a much smaller investment. In my region, DMG MORI service (while also far from perfect) has the best availability of any major brand.

Mazak support is non-existent in this area, and despite the marketing pushed by distributors, a DN horizontal is not at all in the same in the same performance category as a premium Japanese machine.

 

[Houdini]

IMHO this impression is why folks need to be careful about the echo chamber that forms in places like this.

The NHX4000 and NHX5000 are far from perfect, but on paper they outperform a similar Makino for a much smaller investment. In my region, DMG MORI service (while also far from perfect) has the best availability of any major brand.

Mazak support is non-existent in this area, and despite the marketing pushed by distributors, a DN horizontal is not at all in the same in the same performance category as a premium Japanese machine.

True, the echo can be loud, and long.
From the average opinions, I have heard their macheens are great, top of the line,
but at the same time, have heard that they have the most issues also.

One of my trainees is now a Makino 5 axis guy at Boeing, he/they said they hate their DMGs the most, and like their Mazaks the most.
So the chamber goes outside of here also.

 

[boosted]

True, the echo can be loud, and long.
From the average opinions, I have heard their macheens are great, top of the line,
but at the same time, have heard that they have the most issues also.

One of my trainees is now a Makino 5 axis guy at Boeing, he/they said they hate their DMGs the most, and like their Mazaks the most.
So the chamber goes outside of here also.

First of all, a DMG and a MORI are two very different products.

Second, Boeing has a unique relationship with Mazak, who got in early and often. They literally have a salesman that services their account exclusively. Boeing is also a special case, because they will keep a machine for 30 years, and they never need it to actually make money.

I really like my DMG's, but to give Mazak credit where it's due, they are probably the best brand out there for long term support. You can still buy parts for 90's Mazak machines, no problem. The Germans don't give a f---. That machine's obsolete the minute it hits the floor. You're lucky if you get 10 years of product support from most German builders. It takes Boeing that long to prove out a new production line.