First layer after raft curling on the Z18

[Arafat Terron]

Hello everyone, this is my first post so I will briefly introduce myself. I'm a Design Engineer Engineer, the company that I work for is looking to get into 3D printing. I have been currently working with the Replicator Mini during the past months to figure out how the technology works. Now that we have some understanding of the technology, we acquired a Z18 and I'm starting to test it.

One of the issues that I have found is when I'm printing large flat surfaces (I was testing with 6"X6" plates) right on top of the raft, the first layer starts to curl, then the extruder starts to make contact with the curled print. This will lead to an extruder error or finish the print but the first layers look awful. I'm using MakerWare Desktop and the default profile which has been working really good for parts without large flat surfaces.

One solution that I found is to modify the raft. I don't use the raft surface layers and instead I add 2 more raft interface layers. The profile would have these 2 parameters modified:

"raftInterfaceLayers": 3,

"raftSurfaceLayers": 0,

In case the first layer quality is not that good, the interface density can be modified.

Another solution that I think might work is to reduce the gap between the raft surface and the first layer, but that would make the raft harder to remove form the print.

I would like to hear your conclusions about this issue and hope it works for someone else.

[Joseph Chiu]

You are over-extruding or are too close to the bed.  The excess material is buckling upward.

[Arafat Terron]

Thanks for the reply. I'm actually working with the over-extruding issue. I am figuring out how to print at 100% infill some castings that needs to be machined and over-extrusion seems to be one of the problems.

[Joseph Chiu]

If you are fighting over-extrusion, defeating that will solve a lot of issues.  Good luck!

We just exhibited at CES last week, showing off the ideaPrinter F100L as an alternative for people looking into the Z18 for its build height.  I'm curious what applications you got the Z18 for?

Thanks!

[Jeff Davis]

Why are you printing with a raft when you have a large flat print area to begin with?  A raft is for parts that don't have a large flat first layer.  Also, is that ABS you are printing?  I know the Z18 has a heated chamber but I don't believe it has a heated build plate.  ABS will not work well with a HBP.

[Arafat Terron]

I have not found the right setup to print raftless. Every time I try, the first layer doesn't stick well to the plate and then it is a mess. I'm printing PLA, the smart extruder for the Z18 is not supposed to be used with ABS.

[Quinton Burcar]

What is the build plate on the z18?

[Jetguy]

No, this is completely false information "the smart extruder for the Z18 is not supposed to be used with ABS."

The extruder is FULLY capable of printing ABS and likely would work a heck of a lot better with ABS than it does with PLA.

BUT, since MakerBot only sells the 2X with a heated bed and markets that as "the" ABS printer in the lineup you are repeating bad information.

[Arafat Terron]

INJECTION MOLDED PC-ABS  According to MakerBot; and the tape is not specified on their webpage, it is a thin sheet of rugged plastic on top and adhesive on the bottom.

[Quinton Burcar]

I was gonna say, if theres a way to switch over to glass (not sure if its possible on 5th gens, but i'd assume theres still a limit switch you could fool) you would be leagues ahead. 

[Jeff Davis]

If the Z-18 is like my standard gen-5 then it has a removable glass plate.  What I have found that works right on the glass (no tape) is using the Aqua Net (Extra Super Hold) hair spray.  Put a nice coat on the glass, let it dry.  If you are printing at the correct height for the first pass then it will stick great!  From your picture you show, the size of the flat area you are printing, I'll bet you can't pull it off the glass when done.  You will need to put the build plate and part in the freezer for 10 minutes and then it will fall off the glass.

Jeff
http://homecnc.info

[Lassi Kinnunen]

don't use raft + use something like a known working hairspray or pva glue.

-lassi

[Wim Vandeputte]

The build plate is a flexible ABS base (which you need to be able to bend if you want to remove large objects) with a sheet of BuildTak

http://www.buildtak.eu/

Great stuff, I use it on the R2, R2x, Mini and Z18. The R5G has a calibration procedure that burns holes in it so can't use it there.

A glass plate would be a problem for removing large (30 x 30 cm) objects 

Arafat:

If you have problems with printing without a raft, then try adjusting the z-offset

Either use the Utilities -> System Tools -> Calibrate Z offset on the machine (you can put a small shimm on the round metal contact point to trick the system in thinking it needs to put the nozzle closer to the buildtak) or plainly give it the absolute offset value in Makerbot Desktop (it's under Devices -> Device Preferences)

Your print looks like very ripe brie cheese... what kind of filament are you using?

Wim.

[Jeff Davis]

I'm testing the buildTax surface right now on my Gen-5.  I put a small pieces of tape at the center to keep the nozzle from burning it when the Z sensing happens.  The other issue with using this on a Gen-5 is that at the start of a print, a Gen-5 will always run a bead line at the front of the stage.  You have no control of this and it keeps putting the same line over and over in the same place on the buildTax.  So after a short while that area will not stick well anymore.

Also BuildTax is on Amazon.com Too

As for the Z offset you can do from Desktop, I have not seen it work as well as doing it in a custom profile (Z-offset)

Jeff
http://homecnc.info

[Arafat Terron]

So BuildTak is the name, it is amazing, at least compared to the blue tape used on the Replicator Mini.

Thanks for the advise, Wim. I wasn't sure which parameters I needed to modify in order to accomplish a raftless print. I'll try your suggestions later.

I'm using Makerbot PLA filament

[adam paul]

While I found the adhesion of buildtak excellent, the durability lacked. definitely don't wipe it with acetone

On Wednesday, January 14, 2015 at 11:37:26 AM UTC-5, Arafat Terron wrote:

So BuildTak is the name, it is amazing, at least compared to the blue tape used on the Replicator Mini.

Thanks for the advise, Wim. I wasn't sure which parameters I needed to modify in order to accomplish a raftless print. I'll try your suggestions later.

I'm using Makerbot PLA filament

On Wednesday, January 14, 2015 at 12:46:00 AM UTC-8, Wim Vandeputte wrote:

[Ryan Carlyle]

Buildtak is a TEMPORARY build surface. You only get so many prints in the same place before it loses stick. Make sure you move your prints around in the build area to get the most life out of it before you have to replace it.

[Arafat Terron]

Lol, never thought about doing that, not sure if you are using it to remove plastic glued to it because for me the raft is removed without leaving any trail. Somewhere in Makerbot I read that you only need to use rubbing alcohol to remove the oil left from fingerprints.

[Joe Soap]

BuildTak is a temporary build surface. However once  you get your
printing parameters and levelling right one sheet lasts for dozens of
prints - mine last for a month or more, with no cleaning required
between prints.

I don't find an issue with it losing grip in a localised area, so moving
stuff around isn't necessary.  I usually end up having to replace the
buildtak sheet because I managed to ram the first layer too close, and
then it sticks so well parts of the print get left behind. Those odd bit
can usually be sucked off by performing another print over the top.

[Wim Vandeputte]

Yes, never use solvents like acetone on buildtak, the documentation recommends Isopropyl alcohol. 

The durability is not that bad, the major complaint I have is that it sticks too well and if you remove large objects, it sometimes stretches the surface up to the point bubbles form and they are not easy to get rid off. Sometimes I feel like putting a hot iron on it but that might not be a good idea ;-)

[LB engg]

I am able to print without rafts on a Z18 by changing the bed z-offset to -0.40mm.  You can do this two ways...either in a custom profile or go to the Devices\Device Preferences\Z-axis offset menu.  NOTE: The latter is a global change. Here is the Makerbot link on how to do it: http://www.makerbot.com/support/new/03_Replicator_Z18/Knowledge_Base/Manually_Adjusting_the_Z-Axis_Offset. 

Using a glue stick on the Build-tak (build plate tape) helps keep the part stuck to the plate during the print.  I can do several prints on the glue before cleaning it off with rubbing alcohol. 

One other thing, I found PLA prints better on the Z18 at 220-223C, extruder speed @ 80mm/s and travel speed @ 140mm/s

On Tuesday, January 13, 2015 at 2:12:20 PM UTC-6, Arafat Terron wrote: