A better Anchor

[Tyler Pope]

I've been very frustrated with the way the anchor only works 50% of the time since upgrading to accelerated printing so I created the zig-zag anchor pictured above in my start.gcode file. So far it's working great.

To use it copy and paste the following into your start.gcode after "(**** end homing ****)"

G1 X-70.5 Y-74 Z150 F3300.0 (move to waiting position)

G130 X20 Y20 Z20 A20 B20 (Lower stepper Vrefs while heating)

M6 T0 (wait for toolhead, and HBP to reach temperature)

G130 X127 Y127 Z40 A127 B127 (Set Stepper motor Vref to defaults)

M108 R3.0 T0

G0 X-70.5 Y-74 (Position Nozzle)

G0 Z0.2      (Position Height)

M108 R4.0    (Set Extruder Speed)

M101         (Start Extruder)

G4 P2000     (Create Anchor)

G1 X-80.5 Y-64 F1500.0 (Create Pre-Anchor extrude)

G1 X-90.5 Y-74 F1500.0 (Create Pre-Anchor extrude)

G1 X-100.5 Y-64 F1500.0 (Create Pre-Anchor extrude)

G1 X-110.5 Y-74 F1500.0 (Create Pre-Anchor extrude)

G1 X-110.5 Y-64 F1500.0 (Create Pre-Anchor extrude)

G4 P500     (Create Anchor) 

(**** end of start.gcode ****)

[andrewupandabout]

Tyler, just put together a video on your zig-zag anchor line. Thanks!

http://www.youtube.com/watch?v=ftTKoVY_BBQ 

Andrew

[Joseph Chiu]

Is the main intent to prime the extruder?  I've been using outline in my setup for that purpose.

Are anchors really used as anchors to help pull out filament?  It seems like a misnomer to me...

[Andrew Mazzotta]

Yeah, anchor seemed to me "to anchor the raft" but my rafts are hardened to the build platform like glue these days!

On Thu, Aug 2, 2012 at 1:31 AM, Joseph Chiu <joe...@joechiu.com> wrote:

Is the main intent to prime the extruder?  I've been using outline in my setup for that purpose.

Are anchors really used as anchors to help pull out filament?  It seems like a misnomer to me...

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[Cymon]

Yeah, anchoring is more of priming the pump. You can just turn on outline to do the trick but that extrudes too much. Instead I'm going to revisit my idea of making something a bit more... sharable that I wrote about here: http://joesmakerbot.blogspot.com/2012/07/hacking-er-improving-startgcode.html

On Thursday, August 2, 2012 8:31:53 AM UTC-6, andrewupandabout wrote:

Yeah, anchor seemed to me "to anchor the raft" but my rafts are hardened to the build platform like glue these days!

On Thu, Aug 2, 2012 at 1:31 AM, Joseph Chiu <joe...@joechiu.com> wrote:

Is the main intent to prime the extruder?  I've been using outline in my setup for that purpose.

Are anchors really used as anchors to help pull out filament?  It seems like a misnomer to me...

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[Tyler Pope]

Thanks for the credit Andrew. If you do a video on modifying the start.gcode file you might mention that once you get it the way you like it to save it there.

[Andrew Mazzotta]

I'm away from my computer I use to build in ReplicatorG so is there a default save setting to save the changed anchor? Thanks!

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[Dan Newman]

On 3 Aug 2012 , at 9:09 PM, Andrew Mazzotta wrote:

> I'm away from my computer I use to build in ReplicatorG so is there a
> default save setting to save the changed anchor? Thanks!

You manually edit the start.gcode file for that machine. I cannot
vouch for where that file is on Windows, but on OS X look in

/Applications/ReplicatorG.app/Contents/Resources/machines/replicator/

The files you want are

Dual_Head_start.gcode
Dualstrusion_start.gcode

and, if you believe in being thorough,

Single_Head_start.gcode

You'll want to edit those with a vanilla text editor. Pulling them
into MS Word would be a mistake.

Dan

[Andrew Mazzotta]

Notepad++ or Codeblocks are favorites.

I will look into this. Thanks Dan.

Dan

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[Dan Newman]

FWIW, the mechanics are as follows

1. In RepG you selected a "Machine Type (Driver)…" with the Machine menu.
Those "types" come from the XML files in C:\Program Files\ReplicatorG\machines\
(I'm guessing at the path -- I'm not much of a Windows user). In those XML
files, different machines are defined. The definitions for the machines
includes an XML tag called "bookends". It tells what files to use
for the start and end gcode blocks. It gives relative paths to those
files.

2. When you slice a model, the gcode generated by Skeinforge is
prepended with the contents of the start gcode file and appended
with the contents of the end gcode file.

3. FWIW, there's an alteration plugin in Skeinforge which, when activated,
attempts to pull in the named start and end gcode files from the Skeinforge
profile's alteration directory. (A directory which is part of the on-disk
representation of a SF profile.) BUT, whether or not that plugin is
enabled, RepG overrides the settings for that plugin with empty strings
for those start and end files. (And that is done regardless of whether
or not use use Print-o-Matic.) So, the start and end gcode files
associated with the alteration plugin of skeinforge are essentially
ignored. So, if you edit those files looking for an effect you won't
see any. At least not with RepG 37, the current release. I mention
this as the old approach back in RepG 29 and earlier was to edit
those files in the alteration directory.

Dan

[Cymon]

I promised Andrew a tutorial on my blog for how I'd do this. Unfortunately this weekend was taken over with Etsy orders so I'm still wrapping up the experimentation phase. But once I have some good test runs I'll update joesmakerbot.blogspot with something that I think is even better than the zigzag and post the files here.

[Luis E. Rodriguez]

Does skirt with a layer of one not work for you all? Just delete anchor gcode. Done and done. 

</ifitaintbroke>

Luis E. Rodriguez

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[Shawn]

The intent goes something like this: "We want to modify the anchor so
that the nozzles are primed, but not waste plastic.".

And in some cases using a skirt will use more plastic than the anchor code.

So, using a skirt may be reasonable sometimes, but otherwise does not
achieve the objective.

At least that is what I've gleaned from watching this discussion the few
times it has come up.

On 12-08-05 11:43 AM, Luis E. Rodriguez wrote:
> Does skirt with a layer of one not work for you all? Just delete anchor
> gcode. Done and done.
>
> </ifitaintbroke>
>
> Luis E. Rodriguez
>
> On Aug 5, 2012, at 12:19 PM, Cymon <joeal...@gmail.com

> <mailto:joeal...@gmail.com>> wrote:
>
>> I promised Andrew a tutorial on my blog for how I'd do this.
>> Unfortunately this weekend was taken over with Etsy orders so I'm
>> still wrapping up the experimentation phase. But once I have some good
>> test runs I'll update joesmakerbot.blogspot with something that I
>> think is even better than the zigzag and post the files here.
>>
>> On Sunday, July 8, 2012 2:42:58 PM UTC-6, Tyler Pope wrote:
>>

>> <https://lh6.googleusercontent.com/-MmZMADNYqB8/T_nwmHz8W7I/AAAAAAAACeM/aujtQLYyFws/s1600/CameraZOOM-20120708153924906.jpg>

>> <mailto:make...@googlegroups.com>.

>> To unsubscribe from this group, send email to
>> makerbot+u...@googlegroups.com

>> <mailto:makerbot+u...@googlegroups.com>.

>> For more options, visit this group at
>> http://groups.google.com/group/makerbot?hl=en.
>

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[Cymon]

Exactly. The skirt solves one problem: the blob. Not the blob at the start of the anchor but the one at the end that needs to be carved off my print. But the skirt still fills up my discard pile with those stringy boogers and i'd rather produce something compact and appealing.

Plus it give us a chance to learn and play with gcode.

[Dan Newman]

On 5 Aug 2012 , at 3:34 PM, Cymon wrote:

> But the skirt still fills up my discard pile with those stringy boogers and i'd rather produce something compact and appealing.

Mind you, those stringy boogers disolve really well with acetone making for a nice stick-to-it
platform.

> Plus it give us a chance to learn and play with gcode.

And that is the best reason to be doing this!

Dan

[Cymon]

I've posted the first better improved anchor with a write up of how I got there. It may be a bit too much information, you can just skip to the end for the results.

http://joesmakerbot.blogspot.com/2012/08/killing-blob.html

I'm experimenting with some other patterns now and I'll probably share a few of them if they work.

[Cymon]

Got another one that may be better for some of you. Prints a test pattern in all four corners to make sure your bed is level before starting.

[Aljosa]

The idea of the anchor is simply to prime the nozzle. What I never liked about the outline/skirt function is that more often then not it was longer then it needed to be. On top of that there was the chance of it not starting correctly, and ending up getting dragged into your print, not to mention its another thing an already slow slicer has to process.

There are many different ways to prime the nozzle, what I wanted with the anchor was something worry free. If you have your bed leveled correctly you can hit print, and walk away without having to worry about threads or dangling pieces of filament that have to be pulled away with tweezers.

The bigger guys get around this by having a waste bin at some location in there printer where the extruder head goes purges, and then proceeds to print. This is also where the extruder goes when switching materials during a print. Something that probably isn't very known is that if you look at the Replicators back panel there is a square that has been scored on the left side of the bot, this can actually be pushed out. In the earlier stages of the Replicator project we actually had a filament purging bin that went in there that the extruder could go to and purge. However we never got the wiping part to where we though it was good enough to put something in there and ship as a product.

All that being said I'm aware of the problem with the anchor when using the accelerated firmware. It does not always work as its supposed to and this is something on my list of things to correct. 

On Sunday, July 8, 2012 4:42:58 PM UTC-4, Tyler Pope wrote:

On Sunday, July 8, 2012 4:42:58 PM UTC-4, Tyler Pope wrote:

[Cymon]

I forgot the link. http://joesmakerbot.blogspot.com/2012/08/killing-blob-2.html

[Cymon]

One more. last one.

http://joesmakerbot.blogspot.com/2012/08/killing-blob-3.html

I say this is the last one because it works the best and uses the least stuff, comes off easily, etc. Not entirely giveaway-able but that's alright. Basically it's the zigzag folded in on itself but I used the principle of skiening a 3D model to find the points I wanted.