Haas UMC 500 alternatives

[EmGo]

Volumetrically, maybe. As for features machined on the same plane, it'll hold a few tenths.

In Z ? I'm sorry, with that ridiculous design, I just can't see it.

 

[mhajicek]

In Z ? I'm sorry, with that ridiculous design, I just can't see it.

I could see it happening within the same part. Cut all the features at the same time and they should agree pretty closely.

 

[EmGo]

I could see it happening within the same part. Cut all the features at the same time and they should agree pretty closely.

Would depend on where in the work envelope. If it was all pretty close to the middle, probably. But look at the thing, all way hung out on two sets of ways. Just the weight of the head will deflect more than a half at the extremes of travel, and that's crediting the ways with a lot more rigidity than they are likely to have. And we aren't even taking into account that no matter what, materials deflect. How much does the spindle weigh ? Hang that out 18" from the nearest support, that's going to be a few tenths right there, even if it were solid.

I just can't see that thing working for shit. The whole idea behind that design is retarded.

This thing with people talking tenths, I dunno ... had a Landis that must have weighed 6,000 lbs ? Probably more ? 20" wheel, the thing was sturdy as heck. The neighbor used to like to come over to chat and lean on the thing. With Etalon indicating mikes I could measure the deflection. He got huffy when I asked him not to lean on the grinder, didn't believe me

But still, a tenth is a tiny little amount. One doesn't "hold tenths" like you were plowing a field or something. I just have a really hard time believing most of this talk.

 

[EmGo]

I could see it happening within the same part.

Let me toss a picture up, ten thousand words and all that. This isn't Haas but it's the same stupid design. How in the hell did this abortion ever get off the drafting table in this day and age ? It's obviously going to work about as well an ornithopter

 

[mhajicek]

Hang that out 18" from the nearest support, that's going to be a few tenths right there, even if it were solid.

Yeah, everything is rubber, and it will sag. But does it sag the same amount each time? If it does, you can hold tenths with it. You'll get more dimension creep with cutter wear though.

 

[Digital Factory]

In Z ? I'm sorry, with that ridiculous design, I just can't see it.

A bit worse in Z, but as @mhajicek said, it'll generally be pretty good within the same part. The larger the part, the more variance you'll see due to nose droop. Small parts are generally unaffected by the nose droop.

Z also drifts over time due to not-so-great thermal comp, so single piece flow is better than dense fixtures, pyramids, etc. Again, the SS models are worse than the regular models in this aspect due to greater heat in a faster machine.

When you begin flipping the part around and rely on Z to hit two opposite faces, or try to connect a bore from two sides where they meet in the middle, that's where the UMC struggles. This is compounded by the fact that this strategy doubles the error.