Hello to all,

[SkyQuake]

Hi Team FDM and everyone.

My name's Mike, and I'm a Chartered Mechanical Engineer from Cambridge in the UK.  Currently in the process of building my first Voron 2.4.  I'm fairly familiar with FDM, SLS and DMLS processes professionally, and I've done a fair bit with CNC machining (built my own in the garden shed!) but this is the first time I've delved into 3D printing for myself.

I mainly want the Voron to build Kit Car parts and guides/tooling for GRRP moulding.

Many thanks for keeping this great resource running.

Cheers,

Mike

[Demosth]

Thanks for the intro, glad to have you on board - I always love seeing Mechanical engineers join the community. It brings a certain viewpoint that i much respect.

You mentioned, "GRRP moulding" - what exactly is this? DO you have an examples to share?

[SkyQuake]

Hi Demosth,

Thanks for the welcome.

GRRP is a typo for GFRP, or Glass Fibre Reinforced Plastic.  Up until now I've been making plugs for parts by hand, or using the CNC.  I then spend ages sanding and polishing them, before wet laying glass fibre over them.  I'm hoping being able to print the plugs will speed that process up somewhat.  I'll still be sanding and polishing, no doubt, but it'll definitely be quicker!

[Demosth]

Thank you! 0 I was searching all over for GRRP thinking it was something i hadn't heard about, but GFRP came up a lot in my searches.

Is it possible to make a 3d printed  "mold" or a part to create a a mold for your "plugs" to reduce teh sanding and shaping? I'm thinking laying the fiber glass in the mold opposed to over the plug?

Thanks!

[SkyQuake]

Hi Demosth,

Yes, certainly, for certain applications.  i.e if you are able to use the 3D printed part to mould the B-side of your component, this this will be fine.  There may be increased difficulty of de-moulding depending on the geometry, but if you have reasonable draft angles the texture of the printed part shouldn't be an issue

In my experience however, the effort required to dress and tidy the A-side is increased, as it's never as uniform as if you'd laid the A-side down in a polished mould.

For most applications, I think I am more likely to Print the part that I want, sand and tidy once, to my heart's content, and then form a mould from the printed part.  I can then shell out copies of the finished part.

Still, all this is sometime in the future; I have a Voron to build and tame first!

[Demosth]

Thanks for the explanation - lets kill this Voron build - let us know if there is anyway we can help!

[SkyQuake]

Ok, so so far, my Voron build hasn't gone too badly.  I broke a couple of my printed parts (being a bit heavy handed) and had to get them remade, and I learned an important lesson about doing my research properly, when I discovered that the Stealthburner option requires different fans and stepper motor to the Afterburner!  Doh!

That said, I thoroughly enjoyed the build, and I have to say, I was not prepared for just how much of a work of art the printer was going to be.  All the way through my build I was admiring how beautifully well designed it is, and learning tricks and hints which will be useful for designing my own parts in future.  The only bit of the whole job which I thought was a little artless was the use of double sided tape to attach the case fans around the skirt, which I see they've already fixed in the 2.4 release 2.   It really is some piece of kit!

So, where things stand, I've made it to the point that it's spitting out little ships, and It's not going half bad!  That said, there are two things that are really bugging me.

Firstly, thermistors.  The ones that came with my Formbot kit had no information with them.  I've tried all of the sensor type options, and nothing seemed to make a blind bit of difference.  I consistantly ended up with a 5-6deg difference between the hotend and the bed, and to get the prints to behave at all, I had to up the temperatures up to 5deg over the maximum recommended for each material.  This led me to mistrust the thermistors, and hence I have forked out for some better quality SliceEngineering 300deg ones to replace them.  I replaced both the hotend thermistor and the bed thermistor (by squeezing the new one in next to the existing one, with boron paste!).  Both have been set to the advised ATC Semitec 104GT-2 setting in the config file.

 

I was hoping this would fix the problem, but I still have a significant difference between my sensors.  At the time of writing, my hotend is reading 18.0deg, and my bed 12.5deg, and neither have been turned on for a couple of days; plenty of time to soak to room temperature.   Measurement of the bed from on top, with an infrared themometer gives 21.7deg, so something smells.  Any ideas?

The other thing is how to get the damned neopixels working!  It's really not important, but I can't get my head around these at all!

Any assistance you can offer would be greatly appreciated.

[claudermilk]

Sounds like there's something up with your environment or themistors. I'm looking at mine and it's been sitting cold all night; bed & hotend are within 0.3C and the chamber is about 1C lower. Hotend is Revo Micro, bed heater is Keenovo, and thermistor is a generic 3950.

For the NeoPixels, what's the issue? It looks from your photos that the SB ones are working. I'm no expert at all--I wired up according to the SB manual & wile.e's pinned diagram and plugged into the Octopus NeoPixel port and they just worked. I'll be adding case lights soon which might be more of a challenge. Anyway, more detail might help someone with more expertise diagnose.

[SkyQuake]

Many thanks for your response claudermilk.  Useful information about the how close your readings are. 

So this evening I've run a couple of tests.  I've measured both the hotend and the bed in several places with the infra-red themometer, and they're both at 23deg +/-0.5.  I've then measured the resistance of the two thermistors, and they were within 1k of each other, at 113k on the bed and 112k on the hotend.  According to the RT table for the slice themistor, this should give me 22.6deg and 22.8deg respectively; within spitting distance of where I need to be.   But my octopus is giving me 23.7 on the bed and 17.8 at the HE. 

The bed I could live with as close enough at 23.7, but what's going on with the HE?  Surely if both themistors are giving near-as-damn-it the same resistances, and they're both set to the same sensor type, then I should be getting the same values, shouldn't I?

I have a chamber thermistor too, as part of my tool head board, but I haven't figured out what I need to add to my config file to get that working yet!

I've managed to get the neopixels to turn on, yes, but that's as far!  How to program them to do anything is the question!

[claudermilk]

Here's my printer.cfg section for the chamber sensor:

[temperature_sensor chamber_temp]
sensor_type: Generic 3950
sensor_pin: PF5

For the SB LEDs, so far I'm just taking the pre-defined status scripts and calling them where appropriate. For example, I've inserted a STATUS_LEVELING call at the beginning of the overloaded Z_TILT_ADJUST macro, then a STATUS_READY call at the end. I'll dig deeper into playing with the NeoPixels once I have my case light strips installed (disco time!).

Troubleshooting the thermistors any further is beyond my knowledge.

[SkyQuake]

Hi Claudermilk,

Many thanks for that.  I was making it way too complicated!  I'll try again with your code and hopefully that'll work.

My themistor issue seems to be something to do with my toolhead board.  If I jump the thermistor straight into the wiring loom, I get matching temperatures to my bed.  Wierd, but I'll try a replacement board and see this this cures it permanently!

Cheers,

 

[SkyQuake]

Right, so don't ask me why, but I have now discovered that the problems with my hot end themister are actually caused by my chamber thermistor on the toolhead board.  Turns out all the rewiring I've been doing is a complete waste of time, and all I have to do is unplug the chamber thermistor from the Octopus and the readings from the hot end thermistor are suddently correct!  Doh!

This seems to be regardless of whether Claudermilk's code is in the config file or not.

So my chamber thermistor was connected from CT on the toolhead board to PF5 on the octopus.  There's no second wire like there is on the other thermistors.  Is this correct?

If so, then I guess my THB is knackered!

[claudermilk]

Thermistor should have two wires, polarity doesn't matter. I don't have a toolhead board, so cannot comment on that.