One of the common problems you face with a 3D printer like the Anet A8 is Printbed adhesion. FFF (fused filament fabrication) printers work by laying hot strands of plastic filament on the printbed in consecutive layers. In order for this to work, the filament has to stick on the printbed at least until the end of the print job.
The printbed is equipped with a heating element that helps adhesion. That’s not enough though. By default, the Anet printbed comes with a layer of blue painter’s tape that can help the plastic get a grip on the bed but frankly, it’s not the best. As I found out, there are various ways of getting better results than this.
After my first couple of prints on the Blue painter’s tape, it started to wear off and I had adhesion problems. I replaced it with a new one but it wasn’t perfect.
After reading about it online, I purchased a sheet of BuildTak (13€) and stuck it on the aluminum bed. It worked perfect, to perfect to be exact. The parts were adhering to the BuildTak very strongly. In order to remove them from the bed, I had to wait for it to cool down AND use a putty knife very carefully to pry them off. Some printed objects broke in the process and the BuildTak got scratched. So I had to try something else.
I removed the BuildTak and reverted back to Painter’s tape, and used a Glue Stick to apply a layer of paper glue on top of it. The prints stuck better but it wasn’t perfect. Besides, the tape gives a rough look to the bottom layer that I did not like.
Next, I bought a cheap 240x300mm Glass Picture Frame (2€) and a glass cutter (2€). Ι cut the glass to the size of the printbed (220x220mm) and used the picture frame clips to secure it on the printbed. The glass plate assists in another way too: sometimes the aluminum printbed on cheap 3D printers can get warped. The glass plate helps to make sure the surface is flat.
To assist in adhesion, I used another popular material: hairspray. I applied a generous thick layer, waited until it was dry and repeated. When the printbed heats up during the print, the hairspray melts just enough for the plastic to stick.
I still have to wait until it cools down in order to remove the printed object but, since the glass plate is removable I put it in… the freezer. After about 5 minutes, the object pops off effortlessly. In this way, I don’t have to wait a lot before I can start a new print job.
After a couple of prints, the hairspray needs a refresh, so I apply a new layer on top. If it gets messy I wash it off completely with warm water and soap and apply two fresh layers. In the last couple of months, I found another alternative to hairspray that is even more inexpensive and without any smells.
I use PVA glue (in Greece is usually referred to as Atlacoll wood glue). I mix it with water (50/50) and get a milk-like watery liquid. I apply it on the glass plate with a brush and wait for 5-10 minutes until it dries. It works even better than hairspray. It too may need a fresh layer every couple of prints.
I am thinking of revisiting BuildTak but this time, instead of sticking it straight on the printbed, I plan to use it in conjunction with the glass plate. This, I hope, will make the removal of the printed object easier. Or perhaps I’ll try a PEI sheet (another material, supposedly very good at adhesion). If and when I do it, I’ll update this post.
[UPDATE | 16/8/2017]
I was just trying to print a part that needed really nice mirror-like finish on the bottom layer (it will be used as a front-facing display panel). I did a couple of attempts with PVA glue on glass but the finish wasn’t perfect.
I had to try something else then, so I wiped the glass surface clean and used it just like that, bare. I also lowered the Z-offset just a little (0.550 instead of 0.500) and the line width (0.3 instead of 0.4) so that the printer would squish the filament a bit more on the glass surface. The result was great! The finish is really mirror-like.
So, maybe I have to reconsider this whole bed adhesion thing. I’ll try a couple of more prints on bare glass and see how it goes…