Understandable, but at the same time, I don’t think that sufficient reassurance is possible on this. I expect that the goal of Proofgrade runs counter to this anxiety both in terms of utility as well as business model.
I don’t understand what you are saying. Do you think it is right to claim PG gives better alignment if it actually doesn’t because it is better business?
Yes. And on this one I think it will give better alignment often enough and for enough customers that it does give better alignment.
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How does it give better alignment?
Because for the non-palmercr use cases it is more likely to be uniform thickness and flatness. And for now, more accurately measured since, as you pointed out, the device doesn’t measure the material for the view. So for anybody without calipers, more accurate.
I admit, in the palmercr use case it isn’t more likely to give better alignment, but I expect that use case to be in the minority of uses of the device.
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There have been many reports of warped Proofgrade. People also report getting very flat non-Proofgrade Baltic Birch.
Perhaps it should be:
-
Use Proofgrade materials or enter the measured thickness of the material if it’s not Proofgrade
Because yes if you enter the nominal thickness of material stated on the label it won’t be accurate at all. PG’s barcode will yield a more accurate thickness but I doubt as accurate as actually measuring it yourself with calipers.
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Or,
Use non-warped material (Proofgrade or non-Proofgrade)…
It goes on to say it should be flat. The full quote is:
It is the first two lines I have issue with.
Yes. Alignment should be correct if the materials thickness is entered correctly and the material is flat.
The statement that it will be best on proofgrade is an attempt at an up-sell.
I’m a bit concerned we have to enter height at all. Perhaps autofocus isn’t going to work as advertised.
There are two other things that could assist in alignment in the short term they haven’t implemented yet either, the mythical head camera, and the red laser. Even if the red laser isn’t Coaxial with the CO2 laser, it could still be used to determine a point, or origin.
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They currently use the red laser and the head camera to make a single height measurement for auto focus, but that is done after you have placed your design and pressed print.
Yes. I’m thinking the red laser may be good enough to focus the CO2 laser, but not accurate enough to be helpful with the lid camera adjustment.
I’m anxious for their staff to return from the factory, so they can get back on task with software development.
I’m hoping production gets streamlined enough when my day 22 order is delivered that we will start to see some focus shifted back to software development.
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The quoted spec for the surface measurement is 0.1mm which should be good enough. Who knows if that is currently what they achieve?
A simple set of nice digital calipers should fix this problem.
I have to disagree with your disagreement. 
If the implication that the most accurate alignment could be achieved by only proofgrade material, the list would consist of,
- scrap your non-PG material and use PG
The very mention of entering height for non-PG material negates the premise that PG is mandatory for best alignment results. In fact, they should probably go a step further and mention “exact height as measured by digital or mechanical calipers.” Just because most of us are measuring using calipers to get within a few .000” doesn’t mean that all are. Guarantee some are measuring with a ruler or even just guesstimating.
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Putting all else aside, I don’t find the statement out of line with common practices. For example:
To get the best results, use one of the Hewlett-Packard papers, which were developed especially for HP inks and your printer.
I’m not picking on HP or anything. You’ll find similar everywhere.
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Yes but we are only talking about alignment. You could argue the end result might be better with PG as it is good quality material but alignment shouldn’t be any better.
BTW are there laws about false advertising in the USA? It is illegal in the UK to make false claims about products that don’t stand up to scrutiny.
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Yes, but in practice the FTC only really goes after certain categories of misleading or false claims.
Also, the First Amendment to our Constitution provides for quite a bit of leeway.
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Unfortunately the red laser is also not parallel with the IR laser (by design). The red laser fires down at an angle. This means the XY offset of the red laser’s spot and the IR laser’s spot will vary depending on material height. Of course, the position of the red laser’s spot will also vary within the head camera’s FOV, and this variance is what is used to calculate material height.
I think this is the case, a similar post I made a while ago got a reply of “correct” from Dan.
Though, I suppose once the material height is determined (by sensing the XY offset between the two spots) the red laser spot could be used for positioning on flat materials, the software would just have to use that offset to calculate the true position of the head.
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Yeah i had to deal with that recently on a Facebook Page where someone was trying to claim that the Glowforge would ONLY cut Proofgrade thus Glowforge is a scam Q.E.D.
It did not take much to set them straight, but the perception is already out there
The other issue ,as @palmercr pointed out… buying Proofgrade is unlikely to be an option for us Internationals due to the high shipping & time costs. Until they set up regional distributors this is likely to affect International uptake.
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