E3D Hemera integrated one piece Extruder. I want one on my MK3S  

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@ido-d

Only if you enjoy wasting money. The real reason you want to use hemera is in two parts. A it flicks hotend exhaust away from the print, B the heatbreak extends into the drive gears. there is simply nowhere for flexibles to buckel. Also makes printing more reliable as there is far less room for unpredictable behavior. Furthermore the assembly process is far more forgiving. I have had nothing but issues dropping nuts and little things with the prusa and bondtech "upgrades". They are a pain to install and the design is stupid. Too many parts, parts that could have been cheaper, easier to install, simpler, and stiffer if they used sheet metal. It's like they are using any excuse they can to 3D print.

the hotend asm feels like a finicky mess. Especially compared the the appliances and cars I work on regularly. The real world outside the 3d printing bubble is so much more refined, and the hemera brings a slice of that into 3d printing. The prusa mini seems like a huge step in the right direction, the design removes so many unnecessary parts. Unfortunately I still fault prusa for not using sheet metal, would love to see the prusa design mentally applied to the monoprice sheet metal style. Would come out as much higher stiffness and ease of repair, but with all the wonderful prusa ease of use goodness. Really love the prusa firmware, they took time to make it really wonderful.

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

I have a speculative idea in regards to the filament sensor;

Is it maybe be possible to use the inline filament sensor from the Mini in conjunction with the Hemera hotend?

I don't know if it would connect to the einsy board or if the MK# firmware would recognize it or not. I just thought I would throw the idea out there. I have no intention of purchasing a hemera. Just spit ballling ideas.

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@wdfitzpat

So perhaps better to wait for the MK4 and start saving 🙂

I used to own a MK2S and now a MK3, I always felt the MK2S printed in better quality. I love the MK3 being 24V (heats up quickly), removable bed and I love the power coated pei sheet. But print quality wise its not doing better than my MK2s. Thats why I was looking at the BMG or the Hemera. 

I also saw a Reddit reply from Josef saying not to invest in any of these upgrades. So.... MK4, will you have all the wanted improvements?

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@ido-d

I put 0.9 stepper for X/Y on my i3 Clone. This makes the biggest difference to my stock MK2.5 and MK3s. So if you want to upgrade, then I can recommend to do this step first. Change the X and Y motors. You can stay on stock firmware as steps can be changed in gcode configuration. 

Replacing the extruder will be the next step.

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

Posted by: @nikolai-r

@ido-d

I put 0.9 stepper for X/Y on my i3 Clone. This makes the biggest difference to my stock MK2.5 and MK3s. So if you want to upgrade, then I can recommend to do this step first. Change the X and Y motors. You can stay on stock firmware as steps can be changed in gcode configuration. 

Replacing the extruder will be the next step.

Bit of a ballpark statement there,  🙂  what make and model? All stepper motors aren't created equal unfortunately - there's a good article here that explains why it's not always a good idea to buy some unknown make off ebay etc. you often just don't know what you're getting.  BTW - I have NO association with Lin Engineering and have never used any of their products.

https://www.linengineering.com/resources/white-papers/design-accuracy-comparison-0-9-vs-1-8/

If I can't see a specification sheet from the manufacturer I generally don't buy the product.  

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@stev-10

I usually try to avoid any discussion about quality products from Aliexpress, Banggood, Ebay, Amazon,...

I got mine from printed solid, the LDO-42STH40-1684MAC. So far pretty happy with those.

https://www.printedsolid.com/collections/prusa/products/ldo-nema-17-motor-power-ldo-42sth40-1684

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

I've tried to show all imperfections:

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@ido-d

The thing is, you are design limited. From quality standpoint, you will see limited improvements with the hemera. It is a reliability and ease of use style upgrade. Not really a print quality  improvement, there will be a tangible benefit though it will not be huge. 

@nikolai-r

You are having over extrusion and your slicer appears to be randomly placing your Z-seam. Other than that you would need to get a different printer to get better quality. Something like a sekkit go

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@wdfitzpat

Both issues you're describing are set on purpose. I like to have slight over extrusion to get more rigid parts. It might look like much on this magnified images but it's just around 5-10% over extrusion. Seam position is set as nearest. 

To be clear. Those images are not being made to win any contest. It's just one of my testing cubes. Everybody can print the xyz cube on their MK2/MK3 printers and compare to this images. Maybe it will help people to make a decision if it's worth it to upgrade to new steppers and/or Hemera extruder. But thanks for pointing that out.

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@wdfitzpat

ADD: You will get though a real quality improvements in regards to Flex filament. I'm printing Ninjaflex on this printer with standard speed/retraction settings made for PLA (40-60mm/s). Stringing is also not an issue anymore. So in this case you will definitely get a real improvement over E3dv6 or Mosquito style extruder.   

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@nikolai-r 

Typical, tried to look for that motor on LDO Motors China website for torque curves and model number returns no result. It will be a custom motor made for a supplier via Ali-Express or the like. They don't seem to list any 0.9 steppers on their website. 

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@nikolai-r

Oh yes, I meant and forgot to mention the speed and stringing. The speed will be able to be increased dramatically at the same level of quality or better.

Did not know about the improvement in stringing though, very intriguing. Perhaps this is because of the move to M4 threading on the cold side of the heatbreak. Less low, compared to aluminum and copper, specific heat material for the cooling effects to travel through compared to the M6 threading on the hot side.

On that note it is worth mentioning that steel is better for heatbreaks because you can use a much smaller section width than titanium for a given strength rating. Also the difference in specific heat is not huge something to the effect of 11 vs 7. Which becomes even less appreciable, I imagine, when you have a radically higher temperature differential. Ex 20 vs 200C in an hotend.

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@stev-10

Not sure what you‘re trying to say. Original Prusa motors are also custom made LDO motors where you don‘t have any detailed spec sheets. Printed Solid is providing all the specs. And this model number is well known and can be bought from many different suppliers. If you‘re looking for something specific, feel free to contact them. I had very good experience with their customer service.

You have also the option to contact LDO motors directly and asking for details. BTW: I can‘t find any NEMA17 motors on the LDO website.

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

@nikolai-r

Habit - I built and repaired CNC and custom production machines for a living and like to see exactly what I'm buying if I'm going to change a known working system. I've also done quite a lot of prototype testing and appraisal, some for Chinese companies.  From past experience the suppliers specs don't always match the manufacturers.  I spent quite some time on several visits to China trolling around various manufacturers factories and am aware of their business methods. Generally they build to a price, if you want quality it simply costs more, just some are better at it than others 😉  

Would be nice to have the Prusa specs but it's relatively easy to deduce their performance by reading the firmware and actually testing/measuring them.  I have no experience of 0.9 degree motors so would be nice to see how they compare to 1.8's and it would be mine, rather than company money I'd be spending 😎  

http://ldomotors.com/products/show/42mm-hybrid-stepper-series are all Nema 17, 60mm are Nema 34 and 110mm are Nema 43.  NEMA is an inch system, Chinese tend to use the metric naming system.

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

 

Posted by: @wdfitzpat

@ido-d

The thing is, you are design limited. From quality standpoint, you will see limited improvements with the hemera. It is a reliability and ease of use style upgrade. Not really a print quality  improvement, there will be a tangible benefit though it will not be huge. 

That right there. For an MMU2, reliability is the absolute key.

I think that a dual-drive gear would solve the major MMU2s problems for me - there are others, but this is a biggie.

The idler door. Too tight or too loose. Too tight, the filament won't get in, so won't trigger the sensor and the mmu2 will grind the filament inside the MMU2 as it tries to push the filament in, to no avail (atleast until the sensor is triggered - and I can see it because I soldered an LED to the sensor). This in turn means that when the MMU2 realises that the load isn't working, it can't retract because it's ground away half the filament which is engaged with the MMu2 gears!

Too loose: the sensor is feather sensitive. If the gear/idler can't properly grab the filament, it marches on and doesn't extrude anything, thinking all is fine. If you get it in the sweet spot, great. But this might have to happen another 600 times in a print, and if it fails every 10th time - that's a right pain in the rear.

So I can see the benefit in a dual-drive system, and if the filament is delivered directly into the hot end, all the better. I only have 1 printer, so iterating designs to make it happen is something I can't do. I'll be forever changing over extruders in order to print modified parts until it works. But I'd certainly give it a go if I did have a 2nd printer. It can't be that hard to integrate a sensor near the extruder.

RE: E3D Hemera integrated one piece Extruder. I want one on my MK3S

Posted by: @kieran-s4

. It can't be that hard to integrate a sensor near the extruder.

It's not that hard to put a filament sensor near, on the MK3S the sensor activation point approx 15mm from the pinch point of the extruder rollers. On the Hemera that would have to increase to a minimum of 70mm or so because of the design as the adjustment and release lever is on the top (input side). 

The interesting part is there is no PTFE tube on the hot side the pinch rollers and the distance from the pinch rollers to the heat break tube is very small as is the distance from the input side to the rollers, thus minimising the chances for any misfeed there. (see picture - in left, out right) The maximum retract distance is only 2mm however before you will pull hot filament into the cold section! The recommended retract is only 0.5mm so your temperature and extrusion rates are going to be pretty critical for good quality prints. 

I have an idea on how to integrate one without loosing X movement but until my MK3S kit arrives (on backorder since 4th) I'm stuck without printing all the extruder parts out on one of my other non Prusa printers to see if it's viable. The others are busy with paying projects 🙂