Does the glass build plate have to be pyrex?

[mhackney]

+simple, easy, dead flat, not terribly expensive, acts as a heat dissipator, fast heat up
-not many people have the ability to cut a 12" disk, requires a surface like PEI (a + for me), requires more power to heat up, not really removable so you really should be experienced or you will damage the surface

Historically, riprap printed on glass. Then all sorts of "stuff" was put on the glass to get that first layer to stick - blue tape, hair spray, various films, glue stick, acetone/ABS slurry. Glass is cheap and very flat, heats up fast. It is a simple solution. Lulzbot actually includes PEI (on glass though) with their Taz 5 printer that came out last year and they credit me with my research and writing about it for the change. At this point there is so much FUD out there on print surfaces and beds that no one knows what works and not. It also depends on what filament you are printing. Nylon requires a completely different surface and some of the other high temp filaments do too. But, they also don't print on glass either. Personally, I think glass will go the way of the dodo bird!

[Polygonhell]

The reason glass is usually used as a build surface is that it's cheap, flat and prints will stick to it.

MIC-6 or other cast plates can get quite expensive (I think a lot of the ebay plates are offcuts), if you can get a plate shipped and cut it to size, you'll need to cover any exposed parts of the PCB on the bed to prevent the plate shorting it out, and you'll have to cover the plate with something that the prints will stick to.

Although the temperature will be more evenly distributed with the MIC-6, you may also have issues holding high temperatures, because more heat will be lost through it.

Cover it with PEI and it's a superior solution IMO.

[mhackney]

Forgot to add, several years ago I manufactured and sold a simple 1/8" aluminum heat dissipator here. Filks had problems with "warpage" although I'm still using mine and it is dead flat. But, the reason for mentioning this... to manufacture them in 1/4" MIC-6 would cost more than folks would be willing to spend given a $25 borosilicate glass option. The bed actually should be about 12 1/4" in diameter which throws the entire economics off since the material comes in 12" increments. The machining costs also would be substantial charging reasonable machine shop times.

[mhackney]

I agree with Polygonhell. However, if one takes a "systems" approach the MIC-6 option works fine. On my Kossel250 I have a 1/4" MIC-6 build surface with a Kapton heater stuck to the bottom and PEI taped to the top. So I have the best of all worlds - flat, heat dissipator, rapid heat up, a great build surface and no issues with that pesky "hold the glass plate down" problem that everyone has to some degree but rarely talks about.

[Polygonhell]

Forgot to add, several years ago I manufactured and sold a simple 1/8" aluminum heat dissipator here. Filks had problems with "warpage" although I'm still using mine and it is dead flat.

It's interesting that yours was/is flat, I found mine recently while cleaning out my office, put a straight edge on it and it has a huge bow in the middle (not complaining, you offered a refund). And that's inline with my experience machining 1/8th inch Al in general.

[mhackney]

The issue was the alloy I used when milled was stressed. When these left my shop they were flat but they relieved in shipping (that sounds dirty, sorry!) and that was the issue. I know of several folks still using theres and I have 8 here, 3 flat and 5 warped.

Interestingly most of the bed supports on Cartesian printers like the Taz, etc are 1.8" aluminum and typically have a little warp in them. Combine that with clamping the glass at 4 corners and you have a problem.

[mhackney]

Oh, and another benefit - for FSR based Z probes (or any Z probe that touches the bed with the nozzle) the MIC-6 plate is stiff so there is very little deflection throwing off the measurement. With glass on an Onyx on the snowflake melamine I found that there was enough springiness in that stack to give inconsistent trigger heights. My Kossel250 triggers dead on.

[Polygonhell]

Interestingly most of the bed supports on Cartesian printers like the Taz, etc are 1.8" aluminum and typically have a little warp in them. Combine that with clamping the glass at 4 corners and you have a problem.

Most of the 1/8 inch material I see doesn't even start flat, I always put it down to the nature of the manufacturing process.
Usually since I usually don't have MIC-6 on hand, I'll use 3/16 inch or 1/4 inch and face it if I need something approximating flat, but machining time is rarely an issue for me, since I'm not "paying" for my time.

[bvandiepenbos]

Only downside I can see of mic6 is slower heat up.

Hmmm, maybe I should get in some mic6 & pei ?

Would 1/4" be optimal?

[mhackney]

1/4 is the thinnest it comes. I experimented with 1/4 and 5/16. There is a lot more mass in 5/16! I do run my Onyx at 24V so heated is fast. The caption heater on the K250 has no problem either (also 24V).

[Windshadow]

1/4 is the thinnest it comes. I experimented with 1/4 and 5/16. There is a lot more mass in 5/16! I do run my Onyx at 24V so heated is fast. The caption heater on the K250 has no problem either (also 24V).

What you said about experience tells me to file this away for future reference.... as does you note about using 24 volts...also what you said about the plate needing to be 12.2" in diameter and the stock only either 12" or 24" as stock widths I can turn a 12x12 plate into a 12" circle without a problem but i can't stretch it and as you say the larger width would mean a lot of waste hence raw material cost... what is the problem of the plate being 2/10 of an inch undersize is it just a reduction in build volume?

tonight I reached May 2013 of your 31 page build forum thread. the PT-100 canned replacement of for the fragile glass one .. and it makes very interesting reading as far as i have gotten... I ordures to me that one of these could be inserted into the edge of an Al build plate
But it still looks like a lot of fun to play with in a few months and I can knock out a 12" dia from the 12x12 plates sold on eBay which as you say not everyone has access to with out paying machine shop rates.
I feel very lucky to have landed here for my first experience of building a 3D printer with you and the other guru level experts here so willing to help and share with those of us just starting.

Tonight I am stopping at page 68 and tomorrow I will pick i8t up at
Part7 – Installing the Towers & Tower Wiring

due to an error in shipping I won't get the replacement plates until after 3PM on Friday so plenty of time to get all in readiness for calibration over the weekend... Thats if I don't fail the smoke test
and then I will be following your Strategy for Prints guide
as if it was holy writ

[mhackney]

Eee gads, people actually read my build thread?

There is no real problem with using a 12" disk except that the Onyx mounting holes are on a larger diameter so it makes for tricky mounting. If you use a different heater, you can plan for that. Also, for a commercial aftermarket upgrade, folks would expect to maintain their build volume and having it be 1/2" or so smaller is just the kind of objection to a product that causes problems. Small I know but we humans are a strange lot!

[3D-Print]

Eee gads, people actually read my build thread?

Yep read your thread and the entire manual before I built my printer!!! Thanks.

[bot]

Well I'll cross my fingers. I've got thousands of hours on these mirrors, many of which above 100 degrees, so I think I'm safe (without changing anything drastically).

[626Pilot]

I got my first glass plate from a glass shop in town. I think it was about thirty bucks. They didn't know what a millimeter was, so I told them to make it 11", and specified that it had to be oven glass that could withstand temperatures higher than boiling. They asked what it was for, I said "3D printing," and they gave me a blank stare. A couple of days later, I picked it up.

I replaced it a year or so later on with a boro plate from SeeMeCNC. I just wasn't sure how flat it was, and in the event it had more than a few thou of variation, I didn't want that throwing off my calibration. The SeeMe glass is thinner than what I got from the glass place, and I figured it would be engineered to be as flat as possible.

The most interesting build plate I've ever seen is made out of GRANITE! I don't know how long that takes to heat up, but I bet it takes forever.

[Eaglezsoar]

I got my first glass plate from a glass shop in town. I think it was about thirty bucks. They didn't know what a millimeter was, so I told them to make it 11", and specified that it had to be oven glass that could withstand temperatures higher than boiling. They asked what it was for, I said "3D printing," and they gave me a blank stare. A couple of days later, I picked it up.

I replaced it a year or so later on with a boro plate from SeeMeCNC. I just wasn't sure how flat it was, and in the event it had more than a few thou of variation, I didn't want that throwing off my calibration. The SeeMe glass is thinner than what I got from the glass place, and I figured it would be engineered to be as flat as possible.

The most interesting build plate I've ever seen is made out of GRANITE! I don't know how long that takes to heat up, but I bet it takes forever.

Granite sounds great if the cost is reasonable. I need to check out some local granite sources.
Thanks for the great idea!

[bot]

I would love to use precision ground granite as a base to build up the sandwich from. Everything could be clamped down to it using mic6 plate and precision ground (or just milled) standoffs, ensuring a truly flat plane.

[Windshadow]

Well the precision surface plate I have in my shop is a small one and 4 inches thick and weighs more than 100Lbs...
http://www.starrett.com/metrology/metro ... rior-black
I think heating it might be a bit of a problem....

I expect you are thinking of countertop stone which is mostly an inch or less in thickness.. but it will not be certified as flat I have seen soapstone slabs that are only 3/8 inch thick and I think the flatness used for countertop surfaces will be sufficiently flat over the small area of a build plate for 3D printing. I have friends who are Home shop machinists and they have gone to the local grave stone makes and obtained the stones that have had error in carving or have had cracks that showed up in shipping and they tell me that the standard rock of ages polishing is more than adequate for home shop Metrology I have a Starrett plate because I saw it at an auction and it was only $10 new they are very expensive

in this way as Starrett puts it

Our granite surface plates are:

Meet or exceed Federal Specification GGG-P-463c requirements
Provided with NIST Traceable calibration certificates. A2LA Accredited calibrations are available upon request. Long form, graphed reports of the inspection surface of the granite plate are also available upon request for an additional charge.
Available in Grades AA (Laboratory), A (Inspection) or B (Shop or Toolroom grade).
Available in Crystal Pink or Superior Black Granite.
Produced to support 50-lbs per square foot loading, loaded in the center of the plate.
This means that the designated load may be placed in the center of the plate without deflecting the overall accuracy more than 50%.

[bot]

That's exactly why I'd only use it as a base to build off of. Then, the vertical towers could also rest on the top of the granite surface. Mic6 or even simply glass is flat enough at 12" or so diameters.

[TN Yankee]

What about the basalt plates sold by QU-BD? While I haven't read many good comments about their printers (or at least earlier ones), the basalt seems to be popular. I haven't been able to read what filaments are being used, though.

I'd be curious about one surface that's good for PLA, ABS, nylons & PETG.