We need a simpler I3 mk8 extruder mount design

[hodgepodgerama2]

Hello all,

I'm going to start this discussion on a couple of forums, but since I have an aluminum Geetech I3, I thought I would start here...

Why is the extruder mount assembly so convoluted? Changing out extruder parts should and could be SO simple, but because of the mounting process, mismatched parts and lack of availability of a few basic spare Geeetch specific parts, you have to completely dismantle your extruder to get the aluminum mounting plate off the bottom in order to swap out extruders.

I am a production oriented person who bought a Geeetech so I could figure out how everything works and so I could advance my other hobbies, primarily animatronics and robotics. In a couple of months I've gotten pretty good with the printer and I now own 3 Geetech Mk8 extruders and a couple of Mk9 extruders as well as a whole tackle box full of other mechanical and electical spare parts. I have enough spare parts to build several complete plug and play extruder assemblies. The idea was/is to be able to quickly swap out extruders when one jams or clogs, when going from a single to dual extruder set-up or even when switching from PLA to ABS and back. How many times have you clogged an extruder and had to stop what you are doing, take the whole thing apart, rebuild it, and then start again? I'm running 7-12 hour print jobs all the time now and just don't have time to do that but I do have time to just swap out extruders. Why is that so hard?

So....I tried to replicate the proprietary mounting set up that Geeetech uses. My Aluminum I3 uses a painted steel single extruder hanger, which bolts to a proprietary aluminum plate. The hot-end screws through this plate and into the bottom of the extruder housing. (To get the plate off, you have to remove the hot-end.) The hot-end and another M3 screw hold the plate to the extruder. I asked to purchase a few of the aluminum base plates that Geeetech uses. No response. Then I saw these simple single extruder L-shaped mounting brackets that Geeetech sells. Thinking they would work on my printer, I purchased 3. Although they fit the extruder perfectly, apparently, they are not designed to be oriented the way I have them because the bolt pattern doesn't fit my X-Axis truck. It will not effectively replace the little black hanger. It is close, but doesn't work. This WOULD HAVE BEEN a beautiful solution because you could still dismantle the extruder while it is hanging on the truck and all of the parts, extruder, stepper motor, or even the hot-end could be replaced independently. But it doesn't work. No idea how Geeetech thinks this part should be used....

I'm hoping that a few of you who have Geeetech products and other products have thought about this also and have come up with a reasonable solution. Extruders jam occasionally and the fastest way to get back up and running would be to just swap it out for another one and rebuild the jammed one at your convenience. But without a quick-swap mounting solution, there is no way to avoid having to rebuild the jammed extruder regardless of how many spares you have. I would consider just printing a new mount, but I use PLA primarily and don't want anything to soften up from heat during long print jobs.

You guys at Geetech....feel free to provide some insight or, if you can't do that, tell my how I can purchase some of the little aluminum base plates I'm referring to.

I'm attaching some pictures. One is the underside of a Geetech unit with the stock Geetech mounting hanger and aluminum plate attached. Another is a picture of the simple L-bracket sitting on a stepper motor so you can see how/where it mounts to the extruder. Terrific concept. The third is an assembled extruder partially attached to the X-axis truck using one of those L-brackets. (You can see the bolt that doesn't align in the image) And the last picture is of the aluminum mounting plate that does not seem to be available separately from Geetech.

Any ideas would be welcome!

Thanks,

Scott

[Mark]

You can just contact the sales to buy the one you want, give them the pictures and they will help you.

[hodgepodgerama2]

HI,

Thanks for the response and thanks for posting the message. I previously asked to purchase a few of the aluminum plates but did not get a response from sales.

I think my point is more along the lines of "why is it so complicated" rather than "I can't get the specific part I need." (Although it would have been nice to have been able to just get the part.) Ideally, the L bracket would be the perfect universal solution because you could buy a couple and swap extruders whenever you need to. In fact, that is the route I took. I re-drilled the X-carriage (Truck) so that the L-bracket Geeetech sold me will fit. Now I have 4 different extruders from 2 vendors that can be interchanged by removing 2 screws on the X-carriage rather than having to dismantle half-a-dozen parts to get to that aluminum bracket. And I can still mount the dual extruder when I get around to setting that up. An added bonus was that I no longer need the special 38mm extruder tubes because without the aluminum baseplate, I don't need the extra length.

We all know that 3D printing is fun and rewarding. It is up to vendors like Geeetech to make the mechanics more reliable and simpler to deal with. Geeetech does have several innovative components and their parts are generally better quality then their direct competitors, but the technology is constantly advancing. The key to success in an emerging market is to keep up with the advances. I know you guys can do that!

Thanks!

[Mark]

yeah I think your idea is great, but I wonder after you interchange these two extruders, do we need to recalibricate the distance between the nozzle and bed? how do you keep the same distance and keep printing?

[hodgepodgerama2]

Hi,

I wasn't really thinking about this from the perspective of interrupting a job, replacing the extruder and starting the job again, but I did go ahead and drill out the X-Carraige in the picture to accept the L bracket. I've printed several smaller and two large parts with this configuration and it works very well. There are a couple of advantages to this:

1. The entire extruder can be swapped out by unscrewing two screws.
2. Individual parts can be replaced while it is mounted if you want, without dismantling the base (fan, stepper,hot-end)
3. Since it does not use the 8mm think aluminum plate, I do not need to use the special 38mm extruder tubes. A standard 30mm tube works fine.

There is one small disadvantage. The extruder X position is slightly to the right of the old position so you have to re-calibrate center in your software.

I now have 3 extruders set up this way plus the original one with the aluminum plate and a dual extruder that I haven't used yet. To ensure that all the print heads are at the same height, I just measured the first one (with a 30mm tube), calibrated it, and then attached all the other tubes/hot-ends and tightened them down at the exact same height using a micrometer. The 8mm aluminum mounting plate and the 38mm tube on the original extruder cancel eachother out so that one is also at the same height, although it has a different X-Y position than the other two. I will probably still level the bed after a swap, but at most it will be 1 turn on the end-stop screw to get the height perfect.

The long term solution for Geetech, of you want to pursue it, would be to provide an X-carriage in your printers with multiple screw hols so that different configurations can be used. This will be one for the senior folks to decide if it is better to be open-source and interchangeable, or if the proprietary Geeetech extruder mounting set-up generates enough additional revenue to justify. Basically a marketing question.

Let me know if you want me to send a picture.

Thanks for reading!

Scott

[Mark]

yeah, wanna see it, and thanks for sharing!