New print bed material

I hate glass cutting boards, IMO they suck. Some how my wife always has at least one, not sure where they come from or where the old ones go but there's always one around the kitchen.

Well I finally found a use for them, after becoming frustrated with my aluminum bed and painters tape(I had leveling issues), I saw online that a lot of people prefer glass. So I started my quest for a piece of glass, I had to have something around the house, I found nothing. So I started cooking some lunch and saw the cutting board...eureka!!

Its one with a somewhat textured surface on one side and smooth with a plastic sheet with an inspirational saying printed on the other. I am using the textured side with PVA glue, but I could also peel off the plastic with the text on it and use the smooth side. For now though I am liking the finish from the textured side. If anybody is interested I will post some pics. I have used a heat gun on it to dry the glue super fast, though I don't have a heated bed. I print with pla only for now since I have no heat bed, but I will be getting one soon.

IMO its been pretty great so far, and wanted to share this as a cheap easily available alternative for a glass bed, and are available in all shapes and sizes.

What do you guys think?

I´m using glass picture frames sometimes. They are thin ( heating goes faster ) and flat ( by purpose ).
Not so sure about the cutter boards about their flatness?
-Olaf
PS: You wanna risk a divorce?

Lol to the divorce, I used an old one and got her blessing(the inspirational message on it must not be so inspirational anymore).

I checked for flatness and it was perfect, plus its pretty thick compared to most of the other pieces I found that didn't fit the bill. I know they are dishwasher safe, and have hit it with the heat gun in a spot until it was too hot to touch, so I think it should be good even with a heated bed setup. They seem to cost right around 10 bucks for the cheap ones, so if it breaks its easily replaceable. My problem with the aluminum was flex, when I tightened it down there was too much flex in the panel. I am sure a thicker piece would have fixed that, but I also had my blue tape peel up on several occasions, the object being printed stuck fine to the tape but the warping forces actually peeled up the tape from the aluminum where it was trying to warp.

Idk if all of them will be as flat, but I think a cutting surface, and glass in general, is usually pretty flat. I found a round one on eBay, and am almost done with my custom delta so I will most likely try that one out too.

If you were having a problem with aluminum it is because it was too thin and/or the leveling scheme was wrong (let me guess- screws at 4 corners?).

Aluminum is thermally conductive and is the best thing to use for a heated bed. Many people use glass because they have problems with the thin sheet of aluminum provided by the printer maker because it isn't flat to start with and then they use a 4 point "leveling" scheme.

Not all aluminum is created equal. The right material to use for a print bed is not extruded or rolled sheet. 1/4" (or more) cast tooling plate is the good stuff. It comes milled flat and stays that way when heated.

4- point "leveling" isn't leveling, it's just dumb. It guarantees that the bed and usually the undercarriage, too, will flex. Flexing the bed has obvious consequences for getting prints to stick to it. Flexing the undercarriage changes the alignment of its bearings on the guide rails. Neither of these flexing effects are in any way equivalent to "leveling". A 3-point leveling system will actually level the bed without flexing it or the undercarriage. The presence of a 4-point leveling scheme is indicative of a design by someone who didn't give it much thought. Fortunately, it isn't usually very hard or expensive to convert to a 3-point leveling scheme. If you want to see how to do it right, see my printer linked in my signature below, step 7.

Here's an example of what can be done with a 1/4" aluminum plate and a proper 3-point leveling scheme:



That pulley is about 190 mm diameter, printed with ABS on clean Kapton tape (no glue, hairspray, ABS juice, or any other slop applied). ABS is notoriously difficult to print because it breaks free of the bed and delaminates. This print finished with no delamination and had to be pried loose from the bed. The bed is 12" x 12.5" x 1/4" cast aluminum tooling plate with a 450 W heater and a properly designed 3 point leveling system.

Here's the completed pulley:

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I agree, I always knew thicker would be better, just didn't want to shell out the money for it. Right now I have a 2mm thick plate with 3 screws on each side, though not a proper leveling system. The aluminum is flat though when measured, but during the print it changes, and also the tape comes undone. I didn't splurge on anything fancy because I would lose too much z axis, right now I am down to about 40mm, I hacked my 3020 router to start printing some pieces for a delta setup.

I am shopping for the delta and was thinking about a glass bed for it based on my experience with aluminum. Do you print directly on it or use tape? What do you think the minimum thickness should be for a solid plate? Is the extra cost worth it?

Your experience with aluminum is limited to a poor design. The fact that prints won't stick is not the material's fault.

One reason prints fail to stick to a print bed is the temperature. If it's too low the plastic won't stick. A glass plate is a thermal insulator. You will have hot and cold spots on it. Prints will let go at the cold spots. Aluminum is a thermal conductor and the temperature at its surface will not vary as much as it does with glass.

Another major cause of prints failing to stick is a lack of bed flatness. Thin sheet aluminum is cheap and thermally conductive which is why it is commonly found in printers with heated beds. With no force applied to it it may be flat enough to print on, but the typically poor leveling system usually guarantees that there will be bending forces on the aluminum, ruining any inherent flatness it may have started with.

1/4" cast tooling plate costs more than 2 mm extruded aluminum sheet because it is milled flat. AFAIK, 1/4" is the thinnest milled plate you can get. The grains in the cast plate are random so it will expand evenly with heat instead of warping like an extruded sheet. I can print nearly edge to edge on my 12" x 12.5" plate, so unless you're making a really big machine, 1/4" plate will probably be fine. The inability to go right to the edge is thermal- the edges of a heated plate are always cooler than the bulk of the plate because of the air convection that the heating causes.

I use kapton tape, but I print ABS. Blue painter's tape seems to be the standard for printing PLA.

Many people do everything they can to minimize the cost of materials for a 3D printer without considering the effect of cheap materials and poor design on the reliability of the machine and what a lack of reliability really costs. So what does a print failure cost? There's a small cost associated with the wasted material, but for me, and I suspect most other people, if they thought about it, the time and aggravation of having to restart a failed print is by far the biggest cost of a failure. Let's see, maybe it costs $20 extra to use a cast plate instead of a too thin aluminum sheet. With the cast plate (and a good leveling system) you'll experience fewer failed jobs. How many failed print jobs does it take to equal $20 worth of your time and aggravation? I don't know about you, but I have a limited amount of free time in which to pursue the types of things I want do with my 3D printer. I value my time very highly and don't like to waste it restarting print jobs. For me the decision to spend the extra $20 was a no-brainer. When I designed and rebuilt my printer, I took everything I learned from the numerous mistakes I made in its first incarnation and did everything I could to improve the reliability and print quality of the machine. Now it is almost like an appliance. When I want to print something, I slice the design, dump the gcode to an SD card, plug it in and start up the machine. I come back in a few hours and it's done. It's not perfect- I still have failures once in a while. I spent some money to get the reliability I have now and consider that money well spent.

Edited 1 time(s). Last edit at 08/30/2015 01:47PM by the_digital_dentist.

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I'm a newbie embarking on an i3 and looking for feedback on ideas.

Quote
the_digital_dentist

Another major cause of prints failing to stick is a lack of bed flatness. Thin sheet aluminum is cheap and thermally conductive which is why it is commonly found in printers with heated beds. With no force applied to it it may be flat enough to print on, but the typically poor leveling system usually guarantees that there will be bending forces on the aluminum, ruining any inherent flatness it may have started with.

.

It seems to me that a three point leveling system for the bed will make it easier to level and will not twist the bed - as the furniture makers say, it's the fourth leg that makes it wobble. If I am only going to use three points on the bed then I only need three on the carriage and can redraw it as an "A" frame, see the attached drawing or plate-1.TCW

This arrangement throws up a couple of triangular offcuts that just beg to be made into fillets to hold the Z frame square to the bed which is fine as I have a bit of 3mm aluminium plate lying around and I have the means to cut it so I can make the frame for nothing. My drawing shows detail of bolt holes and brackets which can be ignored but you can see that I am stiffening the frame with 25mm x 25mm angle which is extended at the top to make mountings for spools.

I take the Digital Dentists' point about 1/4" plate being eight times as stiff as 1/8" but it is also twice as heavy. Too, the "A" frame is lighter than the usual "H" frame further reducing the weight of the bed. It seems to me that a lighter bed assembly will follow the movement of the steppers more closely making for cleaner prints, or is this not an issue?

Can anyone see any problems with this line of thinking? I have attached the drawing as .jpg .tcw and .dxf so feel free to play with it if you wish.

I'm in the Farnham/Petersfield area, any local RUGs ?

Edited 2 time(s). Last edit at 08/31/2015 02:46PM by Petruchio.

Three point leveling is definitely the way to go, but I see that you've got the bearings on the base of your A frame placed pretty close together. It would be better to space them farther apart if the design of the machine's Y axis allows it.

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I have a glass cutting board, and it annoys the hell out of me

However im sorry to say the idea of your surface being new, is not new (sorry). It is just a re-discovery, but earns points for the latral thinking.

Glass chopping board is simply tempered/laminate/toughened glass. When that glass breaks it will be into many hundreds of tiy pieces, yes that type of glass. furthermore, you still have to apply a substrate to it, ie the PVA solution.

A good (utopia) print surface will adhere most if not all currently available filament materials (ABS/PLA/HIPS/PETG/LAYWOOD/NINJAFLEX/FILAFLEX/NYLONS etc) using only heat and no additives/substrates/goop/gunk etc and allow printing without warpage and allow removal of printed parts as if they were placed onto the print bed by hand without tack once cooled.

Quote
the_digital_dentist
Three point leveling is definitely the way to go, but I see that you've got the bearings on the base of your A frame placed pretty close together. It would be better to space them farther apart if the design of the machine's Y axis allows it.

Thanks for that, and I think it's a good point. The travel of the bed equals the length of the rods minus the distance between the ends of the bearings so that is easy to fix, longer Y rods.

OK. Here's another idea that may well be considered as a 'new' print surface. This is now my first choice for all my ABS prints for the last 2 days.

( copied from my post on 3Dhubs )

I tested this idea and the results seemed to be ideal. I would be interested to know if anyone else had experienced this.

I printed an ABS part, +50 layers, 85C bed, and no lifting on the corners - and it was clean.

After print, it was easy to remove and the bottom of the print was completely clean.

How ? Simple. I found some plastic sheet left over after covering the kids school books.

It's like vinyl - just thinner and is marked as Removable Self Adhesive Book Cover. Cost was around $2 for a 5m roll.

I cleaned the print bed with Acetone, then laid a piece of the adhesive plastic just larger than the print area I was to print.

I then wiped the plastic with clear plain acetone with the intention to make sure it was clean from finger print oils, etc. The surface of the plastic turned very tacky.

The first layer of the print went down so well, and consistent - far better than I had ever achieved on ABS slurry on the aluminium bed.

After the print, the plastic lifted easily from the print bed - reminded me of those large thin very stretchy wide area plasters used in hospitals when you have an IV inserted. It peeled off the bottom of the print with minimal effort.

Here's a pic of my first layer print in progress :



Update : googled the plastic book cover, and it's PVC.

And PVC glues well to ABS using acetone, so explains why it turns tacky and accepts the first layer so well.

Quote
the_digital_dentist
Three point leveling is definitely the way to go, but I see that you've got the bearings on the base of your A frame placed pretty close together. It would be better to space them farther apart if the design of the machine's Y axis allows it.

Revised drawing attached, the Y rods will need lengthening to 500mm. plate.TCW

Edited 1 time(s). Last edit at 09/08/2015 02:33PM by Petruchio.