There is a chance for damage, yes. It may be small, but it’s not zero.
- The MOSFET could overheat (but very unlikely, see previous post), or
- the circuit path on the board could heat up and break or, worst case, melt (at least the latter one is also unlikely), or
- the power supply could give up due to the additional load, it’s pretty much maxed out already in the stock config. Check your supply for its current rating, you’re using ca. 6.7 A at the moment (2.4 A heatbed + 4.3 A “hot” hotend), not counting the motors.
Therefore, as usual, the recommendation for all kinds of heater power upgrades: use a smoke detector or similar.
On the positive side, the guy who fried his board using the Mk2a heatbed probably drew 15 A from it, so it could be worse. Still, it’s no proof that the above amperage will work over a long time, and even more so, there’s no warranty in case of failure.
Things you can do on short notice:
- if you have the screw-fixed cartridge in the Velleman-hotend, you can use that cartridge in the E3D, too, as you already suggested. Our second printer has this configuration.
- In the firmware, it’s possible to reduce the power used by the hotend. The setting is - as far as I know - not accessible via LCD, so reloading the firmware is necessary for this. This seems to be a very good way to solve the problem, however, the power reduction is facilitated through a low frequency PWM. I.e. during the time periods when the hotend is on, the current is still 4.3 A, so it doesn’t help with the power supply.
Since I’m not really up for the challenge to install that MOSFET upgrade without good explanation on how to do it, I will just change back to the cartridge from velleman.
i already noticed that the heat up of the extrude was twice as fast as before. But since this is not really necessary Its probably for the best I use the one from velleman
With the E3D heater cartridge the heating curve on my printer continuous fluctuated between +10° and -10° Celsius of the desired nozzle temperature and sometimes I got the famous brown out reset.
So I’m using back the original Velleman heater cartridge in the E3D hot end. Works perfect !
Hi fitchie,
Velleman V2 firmware, by any chance? +/- 10 K matches the PID functional range set there.
Cheers,
kuraasu
Yes, upgraded to firmware V2.
On step 2 in the manual for installing the E3D on the k8200 it says two remove these to parts (refering to the thermistor and cartridge from velleman). Maybe you have to change it to “keep these parts and use with the E3D hotend” since the one from E3D is not suitable to fit on a standard k8200 (without MOSFET upgrade)
Something completely else, when googling some things about the E3D hotend I read allot of issues with printing PLA and the retraction of PLA. Is this really such a pain to make it work? Since I only print with PLA because my bed does not get hot enough to print ABS. If so, are there things I have to take in mind when testing out the first test-prints?
Hi fitchie,
it won’t solve the issues mentioned above about the power supply etc., but - for future reference - the following steps will eliminate the temperature oscillation:
- increase the PID_FUNCTIONAL_RANGE (current Marlin version or at least Velleman V2; parameter not present in V1) to 20 or up to 50 (unit is °C, or K to be precise),
- if necessary for very powerful cartridges or increased supply voltage, limit the current both in bang-bang and PID mode (BANG_MAX, PID_MAX), and
- enter appropriate PID parameters (autotune at target temperature, or tune manually if you wish).
A few degrees of overshoot is ok for “perfect” PID parameters, since this is the fastest way to reach the target temperature.
Cheers,
kuraasu
I finished building the E3D hotend and new GT2 belts to my velleman. In repetier I changed only the Nozzle diameter for now. I’m currently using the 0,4mm one (so only 0,1mm difference with the stock one of velleman). Kuraasu also said something about extrusion width so I checked this in Slic3er. It is read in percent depending on the layer height. But why should these be reconsidered when you change the nozzle? Since you already change the layer heights when you change the nozzle? So these values change too I presume?
Hi Kenny,
because there are limitations on how much wider or narrower than the nozzle you can print.
The layer height is also connected to the nozzle diameter - in terms of “there are limits”, not “must be exacty this or that ratio”.
If you lower the layer height corresponding to the decreased nozzle diameter, and all extrusion widths are set as percentages, than it should be fine.
If any extrusion width is set in mm, it may be necessary to adapt the value. However, this is probably only necessary for very large extrusion widths, which are just barely printed with sufficient quality using a 0.5 mm nozzle. For everything below that, the 0.4 mm nozzle should be able to handle it just as well as the 0.5 mm.
Cheers,
kuraasu
Ok, thank you! I finished my first few prints, everything looks OK for now. Only my top layer looks very smeared out when printing with Slic3er. I also tested Cura and then this effect is less noticeable.
The only problem I still have (and thought it would be solved with the new belts) is X/Y wobbles. I started a new topic about this because I really want to get this fixed.
Edit: Another small question: I also bought the nozzle pack with a 0,25 and 0,60mm nozzle. What is the finest layer height I could get before I should change to 0,25mm nozzle you think?
Well, 0.2 mm, 0.15 mm, perhaps even 0.1 mm. There’s no fixed limitation. Just take two things into account, then it should be easy to find the parameters (since they may depend on your filament and printer setup):
- With the percentage setting for the extrusion widths, they get smaller with decreasing layer height, possibly down to the point where the extruded lines are too thin, ruining print quality. Increase the percentage or set absolute values for the extrusion widths for low layer heights to solve this issue.
- At very low layer heights, even with wide extrusion, the extruded volume per time gets very low. Thus, the resolution of the stepper motor is insufficient to ensure constant material flow, resulting in bad quality.
[quote=“kuraasu”]
- At very low layer heights, even with wide extrusion, the extruded volume per time gets very low. Thus, the resolution of the stepper motor is insufficient to ensure constant material flow, resulting in bad quality.[/quote]
What are “very low layer heights”? Below 0,1mm? I would already be very happy with 0,1mm layer heights for fine printing.
Edit: What retraction setting do you use with this hot-end? I still have fine strings of filament when printing fine structures with fine/rapid movements. But the amount of strings is already way less then with the stock hot-end
As I said - it depends.
Try it. Leave the first layer height as it is (to get the same base layer) and lower the height for the other layers more and more, then test-print a couple of layers until you can see whether the infill and perimeters are ok or start to get blobs, holes etc.
Ok thanks 
I’m already getting some good results on 0,20mm layer height next prints i’ll start lowering it. Did you catch my edit about the retraction to use on this hot-end?
Thanks for the help
I’m using the following assumption to calculate the layer height:
Layer height (H) 80% of < nozzle diameter > = extrusion width (W)
Examples:
0,50 mm nozzle : 0.50 * 0.8 = 0.40 mm (H) < 0.50 mm nozzle >= 0.5 mm (W)
0,35 mm nozzle : 0.35 * 0.8 = 0.28 mm (H) < 0.35 mm nozzle >= 0.4 mm (W)
0,20 mm nozzle : 0.20 * 0.8 = 0.16 mm (H) < 0.20 mm nozzle >= 0.3 mm (W)
I already read your layer height calculation on the forum somewhere. I think you can get much lower than what you calculate. The standard nozzle of velleman has a diameter of 0,5mm and I always printed with a 0,20 layer height without much trouble.
Now that everything runs OK I wanted to go back to Cura and I can’t seem to find the extrusion width there? Is it calles differently in Cura or am I just missing it over and over again?
If someone here has some experience with cura and the E3D hot-end (0,40mm) nozzle. I still have allot of issues with retracting since I installed this hotend for some reason. The extrusion motor is calibrated. I have grinded down filament quite fast when printing pieces with allot of retraction.
In Cura I use these settings for retraction:
Minimum travel: 1,5mm
Minimal extrusion before retracting: 0,02mm (i tried up to 0,2mm with allot of strings between the parts as a result)
Speed: 65 mm/s
Distance: 3 mm
I’m already getting some good results on 0,20mm layer height next prints i’ll start lowering it. Did you catch my edit about the retraction to use on this hot-end?