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extruder: Do sanity checks on extrusion rates 

Add a run-time check to ensure the incoming g-code doesn't have a
ridiculously large e move.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2017-01-02 19:22:32 -05:00
parent 5a5bd2596a
commit b26922978a
3 changed files with 23 additions and 5 deletions
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10
config/example.cfg
View File

@ -115,6 +115,16 @@ nozzle_diameter: 0.500
filament_diameter: 3.500
# Diameter of the raw filament (in mm) as it enters the
# extruder. This parameter must be provided.
#max_extrude_cross_section:
# Maximum area of the cross section of an extrusion line (in
# mm^2). If a move requests an extrusion rate that would exceed this
# value it will cause an error to be returned. The default is: 4.0 *
# nozzle_diameter^2
#max_extrude_only_distance: 50.0
# Maximum length (in mm of raw filament) that an extrude only move
# may be. If an extrude only move requests a distance greater than
# this value it will cause an error to be returned. The default is
# 50mm.
max_velocity: 200000
# Maximum velocity (in mm/s) of the extruder motor for extrude only
# moves. This parameter must be provided.

4
docs/Todo.md
View File

@ -58,10 +58,6 @@ Safety features
can be useful to detect a sensor failure (eg, thermistor short) that
could otherwise cause the PID to command excessive heating.
* Possibly implement host based checking on the ratio between extrude
amount and head movement.
* Enforce acceleration and speed limits on extruder stepper motor.
Testing features
================

14
klippy/extruder.py
View File

@ -3,7 +3,7 @@
# Copyright (C) 2016 Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import logging
import math, logging
import stepper, heater, homing
class PrinterExtruder:
@ -12,6 +12,11 @@ class PrinterExtruder:
self.stepper = stepper.PrinterStepper(printer, config, 'extruder')
nozzle_diameter = config.getfloat('nozzle_diameter')
filament_diameter = config.getfloat('filament_diameter')
filament_area = math.pi * (filament_diameter * .5)**2
max_cross_section = config.getfloat(
'max_extrude_cross_section', 4. * nozzle_diameter**2)
self.max_extrude_ratio = max_cross_section / filament_area
self.max_e_dist = config.getfloat('max_extrude_only_distance', 50.)
self.max_e_velocity = config.getfloat('max_velocity')
self.max_e_accel = config.getfloat('max_accel')
self.pressure_advance = config.getfloat('pressure_advance', 0.)
@ -30,7 +35,14 @@ class PrinterExtruder:
move.end_pos, "Extrude below minimum temp")
if not move.is_kinematic_move:
# Extrude only move - limit accel and velocity
if move.axes_d[3] > self.max_e_dist:
raise homing.EndstopMoveError(
move.end_pos, "Extrude only move too long")
move.limit_speed(self.max_e_velocity, self.max_e_accel)
elif move.extrude_r > self.max_extrude_ratio:
logging.debug("%s vs %s" % (move.extrude_r, self.max_extrude_ratio))
raise homing.EndstopMoveError(
move.end_pos, "Move exceeds maximum extrusion cross section")
def move(self, move_time, move):
if self.need_motor_enable:
self.stepper.motor_enable(move_time, 1)