Re: [MakerBot] Squished second layer on the Replicator

[Shawn]

Measure your filament width. Then put that value into the "Plastic" tab
in RepG (when doing the gcode). It looks like you are extruding too
much plastic. So that suggests to me that your filament width is
actually higher than the current value.

I've noticed this with the new pink color as well though. Even getting
the numbers right I still see this a little - but only the first layer
or two. I think I need to set my filament even a little higher.
(measured at approx 1.75-1.79, set width to 1.79).

Shawn

On 12-09-15 10:10 AM, captchemo wrote:
> I've had my Replicator for about a month and a half and seem to have
> worked through most of the newbie stuff. Now, I'm trying to refine my
> prints. I've noticed that on the second layer of my prints the layer is
> "squished" out and leaves the outer edge rough from the random
> extrusions. On the third and later layers, it prints fine. (see
> attached photo) Any ideas as to what could be causing this? I thought
> it might just be my right extruder. I've been having problems with it.
> But I switched to left and ran the same color and different colors and
> it is a consistent problem with both extruders. I've re-leveled the HBP
> both with a closer gap and increased gap to no avail.
>
> --
> You received this message because you are subscribed to the Google
> Groups "MakerBot Operators" group.
> To view this discussion on the web visit
> https://groups.google.com/d/msg/makerbot/-/Qk5XWEyt7xMJ.
> To post to this group, send email to make...@googlegroups.com.
> To unsubscribe from this group, send email to
> makerbot+u...@googlegroups.com.
> For more options, visit this group at
> http://groups.google.com/group/makerbot?hl=en.

[captchemo]

I've often wondered how much affect the filament width has. My measurement was 1.80 and RepG was set to 1.82 which suggests that this isn't the problem. How sensitive is this setting and how else would you tweak this to get different effects?

If its not filament diameter, what else could cause this issue? I'll play with the filament setting tomorrow and see what it does. I never seem to have enough time to play with all the variables. Maybe I should measure all my colors and see what they are. I know red and black did it too....

[Shawn]

Measure your filament when you print. The filament diameter can change
a little over time, I believe. This is due to it responding to the
temperature/humidity of the environment it is in. So, taking of
snapshot of the measurements now may not mean anything in 2 months.

[Jetty]

Regarding the 2nd layer, if you have acceleration enabled, it's could
be due to the 5.5 firmware not having Advance,
and Skeinforge being configured to print that layer at a different
speed than the rest, so you end up getting blobbing
at the start end of the move.

Could also be due to a non level platform and an extruder nozzle
shooting sideways. I had a case recently
where I was getting rippling due to a brass filing being in the
nozzle, this caused the extruder to fire sideways, and
if there's nothing to constrain it (i.e. you have too much space
between layers), then it would blob.

Regarding tuning for fill. There's a bug in RepG's default hexagon
fill, where it doesn't print 100% at 100%.
The fix is to use Line fill instead. There's also a variance in the
pinch wheels on the extruder. Mine vary by
upto 10% from the spec. So what I'm doing now is measure the filament
and put that in printomatic and print a
100% calibration cube with line fill. Then I tune steps per mm for A
and B axis in the xml to get a correct fill.

That way you get the extruders matched.

Oh and, a gotcha, left extruder is the B axis and right extruder is
the A. If you have only one extruder,
then that's A axis.

[captchemo]

I've read a lot about the effects of humidity and temp, and even dust on the filament. I keep all my open spools in 2 gal. Ziplock bags w/desiccant. I'm thinking of unloading the spools from the machine and storing them as well when I don't print frequently. I at least swop them out periodically unless I need a particular color. Also working out a dust cover/shelf to cover the loaded spools...

I am running acceleration right now. I'll try running without to see if this has an affect. Also, I've had lots of issues with leveling. My HBP is warped - Makerbot is going to replace it. Even with this issue, I try and print in a "level" area with a good nozzle height, though this very well could be part of the problem.

The line fill thing is a bit Greek to me I admit. Still trying to figure out all the adjustable variables and how, when, where to mess with them. Is there a comprehensive source for these and what they do? That would be a great resource. Just following this group has been very helpful.

[Fastrack]

If you click the '?' on each "tab" in Skeinforge it takes you to the wiki and the explanations are pretty good on what each item does.

** You may want to select "Duplicate" on the Edit Profiles window... so you can keep the default profile.. Just make sure you pick your custom profile on the generate screen

Gcode -> Edit Slicing Profiles -> pick the one you use in the generate screen and click 'Edit' -> Click 'Craft' -> Click 'Fill'

Scroll down until you see Infill Pattern:

- Grid Circular

- Grid Hex (makerbot default)

- Grid Rect

- Line

I've been using Grid Rect and have been quite pleased with the results, I read on a wiki that it creates a stronger infill because of the way the machine lays it down.

File -> Save and Close

For leveling,  when you get a good HBP invest in a dial indicator you'll save yourself a lot of time!!  I purchased a cheap mechanical one from Princess Auto in Canada and made a mount for it.

Ben

Fastrack on Thingiverse