New K8200 owner!

K8200 3D Printer K8200 - Your printer, creations, and ideas for imp
41

[quote=“peter_the_steam”]Hi There
I have added a Hobb Goblin to my extruder head and found it to be wonderful. No Jamming!!!
If you have access to a lathe, then you can put a nyloc nut in the chuck and thin it down by about 2mm. If you then do not use any of the washers that come with the kit, it will fit.

Alternatively you can print a nut from PLA with a smooth bore of about 7.9mm. This nut can then be force threaded onto the outer end of the Hobb Goblin. You will find that if you get the hobbing central to the feed hole, the hob tends to stay in the right position anyway.

The teeth of the hobbing do not cut into the filament quite the same as the old bolt, but it feeds WAY better.

Another trick I did is to put the filament holder on the LEFT side of the printer. If you manually feed some filament through the hob, then back out again, you will find that the hobbing forces the filament into an even greater curve than normal. The resulting teeth marks on the filament are then on the outside of the curve, and they will rub in the guide. If you try the same thing with the filament on the left, you will find that the filament straightens out rather than curving more. This makes it a lot smoother to feed through the guides.

Cheers
Peter[/quote]

Wow, thanks for the info as well!
I actually tried to make a thinner nyloc nut, but with the grinder and it melted the nylon right out :slight_smile:

Also, regarding the roll position, that’s an awesome idea! I recently for the first time ran a roll way down and it was like a crazy squeaky spring going into extruder! I thought of even making a wire straightener like used all day in manufacturing to straighten prior to entering the extruder.

See here for two new hobbed bolts I made myself! Haven’t tried either yet, but can’t wait.

PROBLEM now… I was printing that rectangular pillar in semiflex/ninjaflex and it was coming out AWESOME! can barely even see layer lines and I’m @ 0.25mm!!!

  • It stopped printing where you see it (I asusme my current hacked hobbed bolt is to blame.
  • BUY, with the glass/heated 60 C/ glue stick topped bed, it was loose and being dragged by the head.

Is there something else that works better w/flex materials and getting to stick to the bed?

I printed that awesome tire and it stayed on…but little surface contact and material to pull / mishape while printing I guess.

IMG_20151015_140925378.jpg?raw=15248×2952

42

[quote=“peter_the_steam”]Hi There
I have added a Hobb Goblin to my extruder head and found it to be wonderful. No Jamming!!!
If you have access to a lathe, then you can put a nyloc nut in the chuck and thin it down by about 2mm. If you then do not use any of the washers that come with the kit, it will fit.

Alternatively you can print a nut from PLA with a smooth bore of about 7.9mm. This nut can then be force threaded onto the outer end of the Hobb Goblin. You will find that if you get the hobbing central to the feed hole, the hob tends to stay in the right position anyway.

The teeth of the hobbing do not cut into the filament quite the same as the old bolt, but it feeds WAY better.

Another trick I did is to put the filament holder on the LEFT side of the printer. If you manually feed some filament through the hob, then back out again, you will find that the hobbing forces the filament into an even greater curve than normal. The resulting teeth marks on the filament are then on the outside of the curve, and they will rub in the guide. If you try the same thing with the filament on the left, you will find that the filament straightens out rather than curving more. This makes it a lot smoother to feed through the guides.

Cheers
Peter[/quote]

Hi I’m still fighting with trying to make my own hobbed bolt. I ruined the stock K8200 with the kit and have tried a couple I made, but they tend to build up with filament fast and stop extruding/slipping.

Question: Does anyone know the actual distance from the bottom of the bolt head on the gear side to the hobbed center? I put a couple m8 x 60 bolts in my machine and measue it to be around 26.62mm - and nobody seems to sell this bolt/setup to that dimension.

Thanks!

43

I simply cut the hobbing of the stock bolt a little deeper with a thin cutting blade of my dremel.
So that it has a little deeper grooves and sharper edges. (not to sharp!)

Works fine for me.
Grinding into the filament is mostly caused by too much pressure of the spring against the filament.

44

[quote=“ichbinsnur”]I simply cut the hobbing of the stock bolt a little deeper with a thin cutting blade of my dremel.
So that it has a little deeper grooves and sharper edges. (not to sharp!)

Works fine for me.
Grinding into the filament is mostly caused by too much pressure of the spring against the filament.[/quote]

Yeah, I am getting it more and more now. I think I had 2 Issues

  1. I am using your mount for the v6 extruder and filament guide.
  2. Since I was using a hobbed bolt I made (because I killed the velleman one) it wouldn’t work without putting the filament guide up high - not into slot you made to mate with the other main piece sandwiched in between the aluminum plates.
  3. So I re-assembled the extruder w/your piece touching/locked in and it wasn’t even touching the hobbed bolt now. I tried going back to the velleman hacked version I have still and got it to kinda print. (starts / stops since my diameter isn’t concentric anymore.)
  4. I think I was hoping to use a different hobbed bolt with your design - Which you made / designed Specifically to work with the stock velleman hobbed bolt!
  5. In turn, to use the stock velleman hobbed bolt, I still had to angle the filament guide just so the spring loaded bearing would even get the filament to touch the hobbed bolt!
  6. For your extruder parts, did you just put all together as it fits by your design and all worked fine or did you have to play with the filament guide so it would allow the bearing to touch the filament / push onto the hobbed bolt???

I think (know) I’m guilty of doing too many changes at one time, heated bed upgrade to 24v, new z axis rod, new extruder hot end, etc etc. and hoping all would just fall into place :slight_smile:
I did goto school for Mechanical Engineering but also have some great combo of ADHD & OCD so it’s very hard for me to do just one thing and test it like I should!!

45

I have just read the posts about the replacement of the hot end with a E3D kit and am interested in fitting one myself. I have a couple of questions about the voltages.
The power supply on the K8200 is 15v but the E3D hot end is rated at 12v, will this cause any problems? I have limited electronics knowledge and simply want to be able to connect the parts to the printer if possible.
As the E3D has an extra cooling fan for the hot end, where do I connect these wires?

Any help would be appreciated.
Thanks

46

The E3D heater is rated for 12V but it will run without issues on 15V too.
I use the E3D heater cartridge on my K8200 for almost 2 years now, without any issues.

As the hotend fan must be on ALL TIME (to prevent jams) the best is to connect it to the 15V input screw terminal
with a small resistor (47 Ohms will do and is widely available) to limit the voltage for the fan to 12V.

47

Thanks for the quick response.
Do I solder the resistor onto one of the wires from the fan and then connect it to the 15v input as though it was just a wire? Does direction matter? Also by 15v input do you mean the terminal block where the power supply connects to? Which mount adapter have you used, the one which I have printed from Thingiverse looks very weak.

48

Just solder the resistor to the positive wire of the fan and connect the other end to the positive oin of the screw terminal.
Negative wire to the ground pin on the screw terminal. (The screw terminal where the power supply is connected)

I made my own design for the E3D mount. Mabe have a look here : thingiverse.com/thing:548827
You will find my other mods there as well.

49

Thanks again.
I have read on other forums that changes are needed to the firmware to prevent overheating and other problems, are these really necessary and if so is there a guide somewhere to help me with this.

50

Not really necessary.
You can run the PID calibration to change the way the heater is controlled.
That will give you more even heating and less overshoot.

51

[quote=“diverkev”]I have just read the posts about the replacement of the hot end with a E3D kit and am interested in fitting one myself. I have a couple of questions about the voltages.
The power supply on the K8200 is 15v but the E3D hot end is rated at 12v, will this cause any problems? I have limited electronics knowledge and simply want to be able to connect the parts to the printer if possible.
As the E3D has an extra cooling fan for the hot end, where do I connect these wires?

Any help would be appreciated.
Thanks[/quote]

Hi,

  • Connect the E3D Fan to ALWAYS on. You can power from the board (tap into the incoming from the power supply)
  • I thought I’d be cool and made a switch for it. I forgot to turn on and melted the mount for the E3D to the Extruder!!!
  • I just connected the hot end to the same exact wires as the stock hot end. Same for the thermister. It’s really a drop in / connect the same deal.