Print Bonding - The Build Platform and the First Layer

Getting prints to bond to the build platform, to not pop off under way, and to not curl and warp can be a challenge.


Glass as a Build Platform

One of the reasons that I bought the Wanhao was for the glass build platform.  Glass presents it's own problems, which I will discuss, but has a crucial advantage of letting you print objects with a perfectly clean face (like the front of an LCD Case).   I am not sure how you would get that with tape and the borders you must have.  I also don't like the idea of taping and re-taping.   I would rather just clean and wipe.

I feel that the only real downside of glass, once you get adhesion right, is that you do lose a little print area due to clips.   I have read that some people use thermal bonding stuff to basically glue the glass to the metal platform but I was not going to go that route.   What I did was craft a little clip that minimizes the loss of platform, and is easy to move from the X to the Y side depending if you absolutely need to max out one side or the other.   The clip,  shown below, takes about 10mm out of the build platform (5mm on each side).

Here are some photos of the parts including the original clip before it met my Dremel.   The original clip is an 8-12mm wiring retainer clip.  The printed piece serves two purposes.  First as a spacer to keep a consistent overlap onto the platform (consistent as in smallest).  The second being that it makes it easier to grab the clip.

My clips are not as tight as a binder clip but I have not found that to be an issue.

Search for "Newlec Edge Beam Clip. For 8mm - 12mm Grip, 10mm - 11mm diameter"

That First Layer

The Wanhao D4S is more sensitive to that first layer than my old printer but only in the sense that I am printing by default at a much higher resolution than I would on my old printer.  New default is .2 and my old default was .3 and sometimes as high as .36.   The old printer was less fussy because it could afford to be!    To print at any resolution you need a good first layer but to print at .1 you need a great first layer.


Platform Leveling

The first part of the answer is to be really finicky about platform leveling.  There is a happy medium between squashing the filament on to the bed to the point where you have a little ridge around the edges to where you don't squash it down and the print pops off the platform!  The ideal case is that you get really good at judging clearance using the piece of paper technique.

The other thing that can help is to download one of the print leveling tools on Thingiverse.  The ones that I mean are the little squares (four corners and middle).  If you print one layer of these squares you can easily see how level your platform is.   I find that you can also watch the print in progress and make some tiny adjustments on the fly.


Clean the Platform, and then, Clean it Again

Before you print anything, including the leveling squares mentioned above, you need a clean build platform.  Obviously if you are using tape then you need, at some point, fresh tape!   I am using glass so will talk about that surface.   I clean mine occaisionally with fine steel wool.   First with acetone and glass cleaner.   Then steel wool again.  Then glass cleaner again.  At this point it is pretty clean!


Goop the Platform

Once the platform is clean it needs a surface preparation that leaves a thin film on the glass for first layer bonding.  I use two treatments with ABS Goop for ABS and Hairspray for PLA.

There are a lot of recipes for ABS Goop out there but I just take a half bottle of acetone and toss in some ABS filament.  A fair amount but 'def not the 1/3 that I have read some people as using.  I then apply to a luke-warm bed using a paper towel and a couple of circular motions. I try to avoid going over the same area more than twice as it should not need it and you don't want either to wipe off what was already put down, or put too much down.   It should look like there is a little haze on the glass.   Here is a photo of a glass plate that has been treated and then used for some prints.

You might note from the overlap that multiple prints, from multiple sessions, have been done from the same cleaning and gooping.  I just arrange where the subsequent prints will go to keep them from overlapping on top of an area that has been de-gooped from a previous print.

On the hairspray side it has to be noted that not all hair spray is created equal.   I have found that "L'Oreal Elnett Hairspray So Sleek Extra Strength" works great while "

Schwarzkopf Supersoft Fixing Hairspray Ultra Strong 250ml

" did not work at all.   Not sure why and have not looked at the ingredients to understand.  The downside of hairspray is that it can be messy.   I have tried to limit this by creating the below applicator.   To be honest I have not used this as of the writing as I am out of hair spray!

As you can probably tell it is part of a cardboard box that snuggly fits the Wanhao build platform with a 3D printed part to help guide the hairspray into the box.   I will update this post next week when I have more hair spray.

Finally, I am having trouble getting PLA to adhere on the new printers glass plate.  I have only tried ABS Goop since I am out of hair spray but it has not worked as well as it does on my Prusa I3.

Clean the Other Extruder!

If you have two extruders, and they don't have the fancy lifter thingy, then you need to make sure there is no plastic left hanging on the unused extruder.   It will grab the print being laid down by the other extruder and pull it off the bed!