Posts made by Lo-Fi

@Phaedrux

Going back over my notes, I originally had extruder max speed at 3600, then subsequently fiddled with it. I've just rebuilt my config entirely and all seems well.

I do still have an issue with the MFM reporting too little movement (<40%) with pressure advance on, though I'm homing in on whether it's slipping itself or whether there is actually some under extrusion going on. My feeling so far is it's struggling to react to rapid moves, but only some slow motion footage will be able to confirm that. I can't hear any skipping and the filament feels like its movement matches the extruder. My prints usually run around the 80-110% mark and I've had the MFM set 70% - 120% for as long as I can remember.

@Phaedrux I think I probably muddied the water by posting the config after I'd been messing with it! You're right, of course.

I'm going to strip it right back and start again - I'll keep the thread updated.

@Phaedrux said in Pressure advance sounds like a machine gun:

M572 D0 S0.05
M566 E1500
M203 E6000
M201 E3000

Thanks for the reply. It was a starting point suggestion from the documentation based on the bowden length. My Pulley ratio is 3.75:1, so I have to be a little careful about speeds and accelerations, as I'm pretty sure those settings all specify conditions at the filament after the gearing, not the motor? I'm running 6mm, 40mm/s retract currently.

Hello!

I thought I'd have a play with pressure advance. I have a printer with a belt reduction extruder and .5m bowden, so it seemed high-time to investigate.

2 problems: firstly, the extruder sounds like a small machine gun half the time. Sounds like a motor missing steps.

Secondly, it fails the print all the time as the MFM calls out too little movement (which I believe is probably correct). Particularly for small features like infill.

I'm running M572 D0 S0.4

I can smooth it out by setting extruder instantaneous speed changes super low (50), but it's slowed things down hugely as your might expect. The extruder is bombproof otherwise - I can't remember the last time I had a movement warning from the MFM.

What, if anything, am I doing wrong? Apologies for the hiatus - usual life stuff, I'm afraid!

Thanks in advance

; Configuration file for Duet WiFi (firmware version 3.3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.3.10 on Mon Jan 10 2022 00:22:29 GMT+0000 (Greenwich Mean Time)

; General preferences
G90                                            ; send absolute coordinates...
M83                                            ; ...but relative extruder moves
M550 P"Ender 5 Plus"                           ; set printer name

; Network
M552 S1                                      ; enable network
M586 P0 S1                                     ; enable HTTP
M586 P1 S0                                     ; disable FTP
M586 P2 S0                                     ; disable Telnet

; Drives
M569 P0 S1                                     ; physical drive 0 goes forwards
M569 P1 S1                                     ; physical drive 1 goes forwards
M569 P2 S0                                     ; physical drive 2 goes backwards
M569 P3 S0                                     ; physical drive 3 goes forwards
M584 X0 Y1 Z2 E3                               ; set drive mapping
M350 X16 Y16 Z16 E16 I1                        ; configure microstepping with interpolation
M92 X80.00 Y80.00 Z800.00 E1000.00              ; set steps per mm
M566 X1000.00 Y1000.00 Z100.00 E50.00        ; set maximum instantaneous speed changes (mm/min)
M203 X12000.00 Y12000.00 Z400.00 E1000.00        ; set maximum speeds (mm/min)
M201 X1200.00 Y1200.00 Z200.00 E1000.00       ; set accelerations (mm/s^2)
M906 X800 Y800 Z800 E800 I30                  ; set motor currents (mA) and motor idle factor in per cent
M84 S30                                        ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1                               ; set axis minima
M208 X350 Y360 Z400 S0                         ; set axis maxima

; Endstops
M574 X1 S1 P"xstop"                            ; configure switch-type (e.g. microswitch) endstop for low end on X via pin xstop
M574 Y1 S1 P"ystop"                            ; configure switch-type (e.g. microswitch) endstop for low end on Y via pin ystop
M574 Z1 S2                                     ; configure Z-probe endstop for low end on Z

; Filament Monitor
M591 D0 P3 C"e0_stop" S1 R70:130 L26.67 E6.0; Duet3D rotating magnet sensor for extruder drive 0 is connected to E0 endstop input, enabled, sensitivity 24.8mm.rev, 70% to 130% tolerance, 3mm detection length
M591 D0 ; display filament sensor parameters for extruder drive 0

; Z-Probe
M950 S0 C"exp.heater3"                         ; create servo pin 0 for BLTouch
M558 P9 C"^zprobe.in" H1 F120 T9000            ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X45 Y0 Z2.399                         ; set Z probe trigger value, offset and trigger height
M557 X45:345 Y25:325 S100                      ; define mesh grid

; Heaters
M308 S0 P"bedtemp" Y"thermistor" A"Bed" T100000 B4138 ; configure sensor 0 as thermistor on pin bedtemp
M950 H0 C"bedheat" T0                          ; create bed heater output on bedheat and map it to sensor 0
M307 H0 B0 S1 P19.56 I0.71 D134.26             ; disable bang-bang mode for the bed heater and set PWM limit
M140 H0                                        ; map heated bed to heater 0
M143 H0 S100                                   ; set temperature limit for heater 0 to 100C
M308 S1 P"e0temp" Y"thermistor" A"Nozzle" T100000 B4138  ; configure sensor 1 as thermistor on pin e0temp
M950 H1 C"e0heat" T1                           ; create nozzle heater output on e0heat and map it to sensor 1
M307 H1 R2.624 K0.576:0.000 D6.17 E1.35 S1.00 B0 V24.2 ;
;M307 H1 B0 R2.451 C156.9 D6.32 S1.00           ; disable bang-bang mode for heater and set PWM limit
M143 H1 S280                                   ; set temperature limit for heater 1 to 280C

;Sensors
M308 S2 P"exp.thermistor6" Y"thermistor" A"Heat Sink" T100000 B3950 

; Fans
M950 F0 C"fan0" Q25                           ; create fan 0 on pin fan0 and set its frequency
M106 P0 C"Part" S0 H-1                         ; set fan 0 name and value. Thermostatic control is turned off
M950 F1 C"fan1" Q500                           ; create fan 1 on pin fan1 and set its frequency
M106 P1 C"Tool" S255 H1 T65                      ; set fan 1 name and value. Thermostatic control is turned on

; Tools
M563 P0 S"Extruder 0" D0 H1 F0                 ; define tool 0
G10 P0 X0 Y0 Z0                                ; set tool 0 axis offsets
G10 P0 R0 S0                                   ; set initial tool 0 active and standby temperatures to 0C

@medicusdkfz

Apologies for the slow reply! Glad it's working out for you

@c310 mag is a little low, AGC is a little high but it should be workable. Try my redesigned housing from the sticky thread in this forum, it'll probably solve the filament skipping past. It'll print fine on an FDM printer so long as the instructions are followed.

The wiring is sensitive to interference no matter how good the continuity might be. How is it routed? If it's close to stepper wiring it's caused communication errors for me. Screened cable seems wise - USB cables are a good cheap source that everybody has. Don't forget to ground the shield only at the board end!

@c310 In my experience, this is typically a wiring or interference issue. Either way, communication has been lost with the MFM during the print. How do you have the wires routed?

That minimum movement figure looks suspiciously low too. That's a separate issue and means that the filament is either slipping in the extruder, or more likely not moving the rotating assembly in the MFM. What housing are you using?

@TheDragonLord

Hi, just found your post - sorry for the delay and thanks! I don't use Fusion so STEP is the best I can do:

MFM Housing - Lo-Fi Lid - mag V2.step

MFM Housing - Lo-Fi Base - mag V2.step

@jens55

Just to throw my 2P worth in.... I run glass on ali and had trouble with the glass taking on the plates shape and having inconsistent flatness. Both solved by dabbing heat transfer compound onto the ali plate in a grid then placing the glass on top. Better heat transfer is a bonus (no waiting for the glass to heat) but the real kicker is the HTC is viscous enough to let the glass sit on it without running away, so the glass can retain it's own (very good) flatness without following the plate. It also stops the glass easily sliding laterally, should the nozzle contact a blob or suchlike. I still run bed comp but I'm well under 0.1mm and so consistent it's almost pointless to remap. I use it to tell me if one of the two Z screws has dropped really, though I should stop being lazy and set them up independent and get the machine to sort.
Removal is easy enough, just pull a single strand of wire through like a cheese wire to break the HTC. Clean and reapply. If you get a hump in the middle, just heat up and put some weight on. Leave it half hour and the glass naturally want to go back to flat, squishing the HTC where it needs to.
I'm not using anything expensive: stock Ender 5 Plus plate and glass bed. Also pulled the same trick on my much Frankensteined Anet A8, the bed of which is truly atrocious but perfectly serviceable with HTC and borosilicate glass slapped on top. It doesn't even have a probe or bed compensation! At the end of the day, ali is terrible at dimensional stability when heated. It's also full of stresses whether billet or cast. If it's not really well annealed to normalise it, those stresses will appear every time heat is applied. Tooling plates should be better than any old cheap slab, of course.
Hope someone finds it helpful, thought I'd throw into the discussion.

@thooijer-0 said in Redesigned the MFM housing:

Thank you for the design , the original i printed skipped.
I noticed without connecting it to the duet.
It will probably work when printed with very tight parameters or with a resin printer.
Your design works good for me, have printed a few objects and it works fine.
Tested the runout function and it is really great! Thanks!

Thanks! I'm really glad it's working out.

@infiniteloop I've seen some interference issues too. In my testing, I found that having the sensor cable too close to the extruder wires would couple cause wacky readings. Move the wiring apart and it all went away. I've not got around to testing shielded cable, but I suspect that would help. Might be worth a try here?

@fcwilt

I've been using cura for quite a while now.

My key things:

Low speed ~30mm/s
Large initial layer ~.2mm
Optimise wall printing order is useful on parts that have many small holes on the bed.
Small hole speed is also useful for getting the small hole walls to stick.
Extrusion multiplier 110% Can be helpful too.
I've found those things make far more difference than different nozzle or bed temps.

That all being said, if you're getting good results from Simplify you ought to be able to replicate in Cura. I assume you're using the same speed, layer height etc?

@brotherchris cheers! Nice to know it's working out

@claustro a pleasure!

Only need little short runs of PTFE, it's just there to provide a nice low friction, non wearing entry and exit and to keep the filament straight as it's passing the hobbed section. Particularly important on setups where the angle changes lots as it looks to be doing with your rig. Without that support, it's not impossible for spring in bending filament to overcome the idler spring and move away from the roller. The holes for the filament in the original design are fairly tight and to some extent serve that function, but will wear over time without the PTFE. May be why you're only seeing the problem down the line.

Interested to hear how you get on, anyway.

What you're describing certainly sounds like a mechanical problem. From the photo, it doesn't look like you're running PTFE in your sensor housing (?), which may a factor. It serves to stabilise the filament path, rather than relying on the idler to provide enough pressure to overcome any force the filament may be applying as it's entry or exit angle changes. It wouldn't surprise me if you found the filament hole in the housing has worn slightly and that's why you're seeing a problem now.

Some further notes in the thread Jay suggests above. I've had zero issues with my sensor since moving to my updated housings and had some good feedback

Keep us posted!

@fma looks like 5mm ID idlers? A piece of 5mm tube clamped with an M3 screw should be rigid enough. The cap heads are often high tensile.

@fma

I'd happily run V1, though you're possibly missing a trick putting the idler pulley on the top left stepper mount hole, then you get V1 belt routing with V2 wrap. Just my thoughts anyway! Nice design.

@pertti Do you have a Z stop switch as well as the BLTouch? If not and you want to use the BL for Z homing, you'll want to change M574 Y1 S1 P"ystop" to M574 Z1 S2 in your config and define a Z homing macro.

This blog post here give an excellent overview of the macros:

https://betrue3d.dk/bltouch-on-duet-wifi-configuratio-and-usage/

Remove the M280 command in the config, that belongs in the Pin Down macro.

@jean-raphael Mine does that... I wondered myself if it's switch bounce which gets ignored after it's triggered anyway. Either way, it functions correctly regardless of the occasional double blink - don't worry about it.

Change the grid Y max in M557 to get rid of the messages about not being able to reach the probe points. Looks like you've got the probe mounted to X-34.3 relative to the nozzle - the opposite to my setup - so it can reach any low value, but not the max.

@jean-raphael

That's not caused by interference, it's because the probe cannot reach those coordinates as constrained by your defined bed size and the probe offset specified in G31.

Post your config.g and bed.g, it won't take much to figure that out.

On my printer, for example, the probe is offset to X+40mm from the nozzle. The nozzle can't go off the side of the bed at X min, so the lowest X position I can probe is X40. Anything lower, I'll get that same message saying those positions in the grid are unreachable.