Yes you right - MAXTEMP for PVA must be around 200C-205C – this variable is precompiled into firmware – the better implementation will be some GCODE’s M - in that case do no need to recompile firmware for different filament (I do not care about this case – but for somebody with switching filament it can be useful). Exact MAX_TEMP depend on hotend parameters, speed of filament in and extrusion ouby alexdobrianski - Plastic Extruder Working Group
Forget another explanation from GCODE of my previous post – layer thickness == 0.33. PVA just solidify right away, set it less == garbage on a nozzle = set it bigger 0.42 (average diameter of a thread) makes line not entirely strait. RepRap Josef Prusa’s calculator (http://calculator.josefprusa.cz/) predict diameter correctly, but flow index does not accepted into account and layer height as 0.2by alexdobrianski - Plastic Extruder Working Group
In another words: MAX_TEMP and MIN_TEMP are essential not mostly by it value, but because it protects again unforeseen problem with temperature control – it switch off heating in emergency situations. PID_TEMP commented out – bang-bang in use == it is better for controlling temperature. PID is also has the problem because at a print time it check temperature with different time interval – and dby alexdobrianski - Plastic Extruder Working Group
That are settings for PVA, on Prusa, Sprinter, RAMPS1.4, in Configuration.h essentials: ------------- #define MOTHERBOARD 33 #define THERMISTORHEATER 1 #define THERMISTORBED 1 #define _AXIS_STEP_PER_UNIT {80, 80, 3200/1.25,526.33} //#define PIDTEMP 1 #define PID_SOFT_PWM #define MINTEMP 5 #define MAXTEMP 275 ------------------- in gcode: ---- (** This GCode was generated by ReplicatorG 0037 **) (by alexdobrianski - Plastic Extruder Working Group
PVA because in need to make molds (http://www.adobri.com/ProjectVe.aspx)– Plastic from Shapeway is perfect for this – alumini can hold up to 180C – enough for my epoxy (first cure must be in mold 92C and second 163C can be done out of mold), but complicated parts require complicated mold - it is much easy to use combined – partly from alumini and partly desolvable. PVA I ordered from Ulimachine.by alexdobrianski - Plastic Extruder Working Group
Well – 9mm/min is working – I totally do not understand that business with 9mm/min – is it suppose to be is a speed of extruder pushing filament into a hot end. I just visually confirm it by gear rotation speed. Then when ReplicatorG generates G-code with that speed (9) set and build started gears definitely rotates slow then for 18mm/min – but it is definitely not a 9mm/min – settings in G-generby alexdobrianski - Plastic Extruder Working Group
Well – result on another night experiments. Sprinter from experimental branch shows the same behavior – swing +-10C. Has some auto-adjust futures. Played with it for couple hours without better then performance, returned back to a “main” Sprinter. Attempt to intensively cool Teflon barrel/brass barrel ( hot end of extruder) by fan (this simulate printing process == pushing filament “adsorbs’by alexdobrianski - Plastic Extruder Working Group
I tried to modify PID, also tried not modified version of PID, and also tried bang-bang. It is properly “upload” to a Mega 2560. I did see difference right away on a graph with two methods to control temperature, and in messages like _DEF_CHAR_UUID. Problem I believe in magic formula, (line with HEATER_DUTY_FOR_SETPOINT). Formula looks like assumed condition that target temperature will beby alexdobrianski - Plastic Extruder Working Group
After yesterday experiments it was confirmed – “PID formula” creates cycles of temperature by itself. Period is 1min 20 sec and period is stable, even 20 minutes it stay amplitude and period the same. To repro situation needs to compile firmware (Sprinter) and monitor temperature in ReplicatorG. That is definitely creates a problem with extruder in my case: for PVA stating flow point is 180Cby alexdobrianski - Plastic Extruder Working Group
I just did simulations of a data using PID - it is looking that the formula not entirely working well. I need to confirm this in experiment but looks like swing inside formula. I assume for calculation the variation 10C during 20 sec loop (as I did see for my case), and just simply calculates all variables in iteration steps in main_heater function inside heater.cpp. Starting from a temperaturby alexdobrianski - Plastic Extruder Working Group
Actually I was wrong about #ifdef – for thermistor TEMP_0_PIN is defined (in pins.h). Also PID_SOFT_PWM defined too - that mean code for temperature adjustment compiled and used for a thermistor.by alexdobrianski - Plastic Extruder Working Group
I am using thermistor 100k, Extruder is a brass M6 barrel, length around 40 mm(http://www.a2aprinter.com/index.php?route=product/product&product_id=68 ), on side of a thread the brass nozzle (http://www.a2aprinter.com/index.php?route=product/product&product_id=63 ). On top of nozzle aluminum heater block (http://www.a2aprinter.com/index.php?route=product/product&path=34&product_idby alexdobrianski - Plastic Extruder Working Group
Hi I posted messages in to separate forums and did not get any response from anybody, may be in “extruder” forum somebody can help me with current problem with extruder. Story described in: Basically today problem is with extruder. I use PVA (I do no need another plastic – just PVA, nothing else suited my needs). PVA melt flow index is 1.5~3.0 to compare with PLA it is 5. That mean needs toby alexdobrianski - Plastic Extruder Working Group
Can somebody correct me: If melt flow index for ABS and PLA is 5 and PVA's melt flow index is 1.5, then for the same pressure PVA will be extruded 1.5/5 = 0.3 amount of regular PLA/ABS. It mean that feed rate must be 0.3*30~40 mm/min = 9-12mm/min. And profilemaker gives in that case for 0.36 diameter = 0.6 for flow rate. Is it true? Actually number looks correct for my yesterday experimentby alexdobrianski - General Mendel Topics
Just for information how problem with extruder was strangely resolved (may be it can be useful to anybody). (beginning of the story in ) After 3 jams Teflon barrel was damaged that extruder was not hold extruder screw, to fix a problem I have to create mettal scuffle to hold extruder on barrel and Teflon plumber tape for insulation/tention. When extruder started to print a calibration cube I rby alexdobrianski - General Mendel Topics
I was not able to solve mentioned problem – ether it is Mega 2650, or RAMPS 1.4 – I give-up – and fix the problem by trading X-axis socket to second extruder socket by changes in pin.c #undef X_STEP_PIN #undef X_DIR_PIN #undef X_ENABLE_PIN #undef X_MIN_PIN #undef X_MAX_PIN -1 //2 //Max endstops default to disabled "-1", set to commented value to enable. #define X_STEP_PIN 3by alexdobrianski - Stepper Motors, Servo Motors, DC Motors
Hi everybody, Can somebody help in problem with hammering noise in stepper motor and not moving X-axis? Story about Mendel Prusa, and it is - Sprinter latest version, with RAMPS 1.4, and Mega 2560 board. Sprinter compiled by Arduino 1.0.1. It was some bugs in compilation which was obvious: In Sd2Card.cpp: ==================================== #if defined(ARDUINO) && ARDUINO >= 100 #inby alexdobrianski - Stepper Motors, Servo Motors, DC Motors