Difference HDZ/ Z-Plus

hi guys, I’d like to upgrade to shapeoko xxl, I’m hesitating between the HDZ and the Z-plus …

what are the differences in use?
for info, I have a makkita router, and don’t want to change in the future, that’s good enough for me.

Thanks for your advice. I appreciate it.
VIVIEN

Hi Vivien,
I’m just starting out myself, but it seems to me that if you never intend moving to a larger spindle and for instance you never intend to (significantly) cut metal then I’d say go for the Z-Plus. Otherwise, to absolutely future proof your machine and you can afford it get the HDZ (but that might be a bit of a wait)

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Relatively new user here as well and I personally own the z plus. I like it a lot, but the biggest drawback I have with the z plus is z travel. When I am using a small endmill, I cannot reach the top of my wasteboard. I have a 3/4 mdf board on top of the already supplied mdf baseboard. I’m actually considering stacking yet another 3/4 on top to eliminate this issue. That would be the main reason I would consider the HDZ over the z plus at the moment. If you’re also considering milking a lot of metal on it then I would probably go to the HDZ just to ensure you have a pleasant experience. I have not cut metal with mine yet so I can’t speak for how well the z plus will do in metal.

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Never say never :slight_smile:

Joking aside, @MarkLince and @shapeokonoob’s answers are spot on.

I’ll add that if you are willing to mill a custom plate, you can get the same Z travel on a Z-plus than on the standard Z axis, see this thread:

Also, this month’s challenge may be an opportunity to win a brand new HDZ 4.0 :slight_smile:

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ok, otherwise the machining behavior is the same for both… precision… ?

@Julien I don’t think I have time for this month’s challenge… and he has so many good projects each time… :wink:

I’m not sure many people have had a chance to try both a Z-plus and then an HDZ, while also keeping track of the precision they are getting, but I may be wrong.

The Z-plus screw uses 200steps per mm, the HDZ is at 320 steps/mm, but I would be very surprised if it mattered in real life, precision-wise.

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Ha…to have THAT problem! I can’t get my hands on either of them for months…so to all of you thinking about comparing them…or upgrading them…boo hoo! :slight_smile:

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I thought the latest Z-Plus is already modified??

Ah, I may just have missed it! Where do you remember seeing that information ?

Ummm, I don’t know, maybe I dreamt it … :wink:

No, the Z-Plus includes an EZ-Tram plate, but they have roughly the same Z-axis travel as the belt-drive units and continue to have the higher mounting (so as to reduce lever forces).

Long term, the HDZ should require less maintenance and adjustment than the Z plus due to ballscrew vs leadscrew.

One day ide like to get my hands on a Z plus to inspect the lead nut.

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good argument… @Vince.Fab

the hdz has more advantages… :slight_smile:

but when is it would be in stock… lol it’s very much in demand :wink:

The step size is tiny and you’re right, compared to the other deflections in the machine the Z step size will not be relevant.

However… The Z plus uses a leadscrew and the HDZ uses a ballscrew, those two really aren’t comparable as the ballscrew is the one designed to not have backlash, lead screws have assorted after-thoughts to work around their inherent backlash. Still, other things on the machine will dominate.

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All this talk about backlash and I was forced to google it. Thinking I may not be the only one, Here is an article I found that explains it. Hope it helps someone besides me.

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As Rob notes we made some changes and a big batch are being assembled as we speak.

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GJM
You are so right. It was called vaporware in my day and referred to a company announcing a product or software well before they were ready to roll out the thing. This was often done because they knew their rival was announcing a new competitive product before them. This is not the case here, it’s the nature of the enterprise. Building a low cost but reliable cnc machine we can all afford. Still, I agree with you the wait for such gripes my ever-loving you know what. I want my toys when I want my toys, LOL. As for the choice between the two, to each his own.

That’s a pretty good explanation. The linear rails and ballscrew on the HDZ deal with the backlash with a similar preload mechanism, the bearings rolling in the tracks are slightly over size and therefore don’t wobble up to a certain load, nothing is truly zero backlash.

Just in case anyone is interested, I stuck a 0.01mm dial gauge on my HDZ and heaved it around with “large cutting force” i.e. about 5kg force up, down, left and right by the spindle and the backlash I measured between the spindle mount bracket and the fixed Z plate on this sample was;

  • X backlash - sod all, squat, couldn’t even see the needle move
  • Y backlash - as above, below my measurement capability
  • Z backlash - < 0.005mm

I think that exceeds any performance we would require of it on a Shapeoko, nice one Luke :wink:

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Does anyone know what the amount of backlash is with the Z+?

I don’t have one to measure, hopefully somebody else does.

Bear in mind though that it’s likely to be a small number in the context of the deflections elsewhere in the machine from the V wheels and belts.

The stock Z had some relatively large unwanted movements which the design of the Z plus removes rather effectively, it has linear rails (like those on the HDZ) so that should be X and Y deflection taken care of and the leadscrew is going to be a large improvement on the old belt drive.

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