Difference between revisions of "Cerealbot"

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=== Types of Failures ===
 
=== Types of Failures ===
  
−
* Loss of filament
+
==== Loss of filament ====
−
* Part traveling
+
 
−
* Misalignment
+
Symptom:
−
* Belt slippage
+
 
 +
The printer continues printing even after the filament is either used, or accidentally breaks due to stress.
 +
 
 +
Abatement Procedure:
 +
 
 +
Prints cannot be saved from this error, but I believe a small analog sensor with wires on the extruder GT2 gear and ball bearing roller can detect the contact between the two items that results from a lack of filament, thus the printer can be autonomously stopped and self-report the situation.
 +
 
 +
==== Part traveling ====
 +
 
 +
Symptom:
 +
 
 +
Sometimes a part will break free from the print bed before it is supposed to, and will drag under the extruder.
 +
 
 +
Abatement Procedure:
 +
 
 +
Possibly a switch attached to a servo with a long wire on it can be swung into contact with the first few layers of a print, and if it detects the print move the job can be stopped and amended remotely?
 +
 
 +
==== Plastic Adhering to Extruder Nozzle ====
 +
 
 +
Symptom:
 +
 
 +
The plastic is either pushed up by the plate, or wraps up on its own and become stuck on the print head. Generally this requires manual intervention to chip off the plastic.
 +
 
 +
Abatement Procedure:
 +
 
 +
I believe that large amounts of plastic may be slowly melted off of the print head, and that the remaining plastic which may interfere with a print can be cleaned by a small field of silicon walls, which can be tested but cutting up a kitchen mitt.
 +
 
 +
* 22-1-2015
 +
** I will attempt to remove cooled plastic from the print head by turning on the extruder fan, and then heating the extruder to 180C. I hope and anticipate that the plastic will slough off and cool on the print bed, where it can be removed remotely.
 +
** visual contact with the underside of the print head is lost, I will have to go on-location to check the progress of this test.
 +
 
 +
 
 +
====  Misalignment ====
 +
 
 +
Symptom:
 +
 
 +
The z-axis can become misaligned which may result in damage to the printer.
 +
 
 +
==== Belt slippage ====
 +
 
 +
Symptom:
 +
 
 +
The x and y axis belts may slip during fast travel on a print, this results in the part printing with slosh or cliffs in either direction.
  
 
=== Contributors ===
 
=== Contributors ===

Revision as of 16:45, 22 January 2015

Creator:
ctag
Status:
Protoype pop-bar installed!
Born On:
23:32, 13 December 2014 (CST)
Last Updated:
16:45, 22 January 2015 (CDT)

Overview

  • Unmodified Printer

  • Unmodified Printer

  • Concept Design

  • Prototype Frame

  • Workspace

  • Climate Container

I am retrofitting a Printrbot Simple Metal 3D printer with tools to allow for serialized printing. Then I hope to release the use of it to schools. For Free.

Cereally 3D Printer Extension

3D printers are nice, but I feel the consumer grade ones are seriously lacking in simple engineering processes that provide a more encapsulated solution. For instance: my printer can not print without me present. Sure, I can start a print and then drive home knowing that for several hours the printer will be occupied without me, but two days later when I next revisist the printer it will have been idle for over 30 hours. I find this unacceptable. Working from a basis of "a good print" where nothing goes wrong, the printer really only requires human intervention to remove the previous part that is firmly stuck to the aluminum plate it was printed on, then it can reset and begin printing again all from software.

The Cereally 3D extension is a project of mine to make the best remote-controlled 3d printer for minimal cost. The keystone for the project is an idea I call the pop-bar, which is an attempt to break finished parts free from the build platform with as little force or complexity possible. I will also investigate other low-cost automation solutions for non-optimal prints, listed below under "Types of Failures".

It is my hope that this project will bring about an affordable printer that can be placed in a school and maintained in a low-overhead, ad-hoc manner. The serialization will also allow for maximal student use from each printer, meaning that more investigative minds have access to this technology.

Progress Log

  • 22-1-2015
    • The second pop-bar, which I am considering a true prototype, has been created and linked to an active servo.
  • Undated, X-1-2015
    • The testbed for train_rec was a success. Rather than use the length of the pop-bar as a lever to pry the piece off of the bed, I think its better to twist the bar along the length to push the 3d printed part up.
  • Undated, X-12-2014
    • Milling the "production/testing" bed is next on the list.

Types of Failures

Loss of filament

Symptom:

The printer continues printing even after the filament is either used, or accidentally breaks due to stress.

Abatement Procedure:

Prints cannot be saved from this error, but I believe a small analog sensor with wires on the extruder GT2 gear and ball bearing roller can detect the contact between the two items that results from a lack of filament, thus the printer can be autonomously stopped and self-report the situation.

Part traveling

Symptom:

Sometimes a part will break free from the print bed before it is supposed to, and will drag under the extruder.

Abatement Procedure:

Possibly a switch attached to a servo with a long wire on it can be swung into contact with the first few layers of a print, and if it detects the print move the job can be stopped and amended remotely?

Plastic Adhering to Extruder Nozzle

Symptom:

The plastic is either pushed up by the plate, or wraps up on its own and become stuck on the print head. Generally this requires manual intervention to chip off the plastic.

Abatement Procedure:

I believe that large amounts of plastic may be slowly melted off of the print head, and that the remaining plastic which may interfere with a print can be cleaned by a small field of silicon walls, which can be tested but cutting up a kitchen mitt.

  • 22-1-2015
    • I will attempt to remove cooled plastic from the print head by turning on the extruder fan, and then heating the extruder to 180C. I hope and anticipate that the plastic will slough off and cool on the print bed, where it can be removed remotely.
    • visual contact with the underside of the print head is lost, I will have to go on-location to check the progress of this test.


Misalignment

Symptom:

The z-axis can become misaligned which may result in damage to the printer.

Belt slippage

Symptom:

The x and y axis belts may slip during fast travel on a print, this results in the part printing with slosh or cliffs in either direction.

Contributors

People who have helped make this happen: 

Phillip Showers
Tyler Crumpton
Hunter Fuller

Thanks!

Software

Network

IP address: 10.56.1.34

Hostname: bns-daedalus.256.makerslocal.org

Public URL: cerealbox.256.makerslocal.org

Services: HTTP-80, WEBCAM-8080

Slic3r Config

Archlinux

To run octoprint from port 80 as user 'octoprint', I adjusted the systemd unit file to launch with authbind. 

[Unit]
Description=Octoprint 3d Printing Web Server
After=network.target

[Service]
User=octoprint
Group=octoprint
Type=simple
ExecStart=/usr/bin/authbind --deep /usr/bin/octoprint --port 80
Restart=on-failure

[Install]
WantedBy=multi-user.target

Right now I'm streaming the webcam from v4l-mjpg-streamer, total pain, will look for something better.

Hardware Configuration

Current

  • Killswitch, both remote and local

Planned

Immediate:

  • Detect use of emg stop button in arduino
  • Pop-bar and channel
    • servo structure
    • Removal arm. Can also double as print surface cleaner?
  • New GT2 belt mount for print bed

Later:

  • Just melt failed prints from the printhead? Then clean with silicon sponge?
  • Use accelerometer to detect grinding gears/belts?
  • larger print surface to maximize hotplate use
    • Longer steel rods
    • more GT2 belt
  • Print a GT2 belt clip? Zipties suck
  • Better webcamera setup
    • different embedded computer?
  • Filament absence sensor
    • Just look for the circuit completion when the extruder rollers connect?
  • Birdsnest detection
  • Print adhesion detection
  • General failure detection
  • Detect belt slipping?
    • Use linear encoders? I mean, they really ought to be standard on a 3d printer.
  • Heater dead-mans switch
    • Ping the webpage?
    • snoop on gcode over serial?

Printed Upgrades

Images incoming.

  • Extruder Fan Duct
  • Filament Guard
  • Filament Clips
  • Spool Stand
  • Filament Cleaner

Upgrades to be printed:

  • Fan mounts for motors
  • GT2 belt mounts for print bed?

Printed Parts

Project Cost Breakdown

Does not include existing things that I own which have been purposed for this project.

dd-mm-yyyy

Project Cost: $683.54

External Resources

Parts

Amazon is an OK outlet for GT2 gear/belt parts for the X-Y motion

Source for 2-3mm Hex Bolts like those used in the simple metal

Pololu for servos

MISC

ctag's G+ Image Album

Printrbot initial config guide

Protoparadigm plastic I'm interested in

Quick guide on authbind, which allows octoprint to bind port 80

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