Gap Between Bottom of Extruder and Top of Aluminum Hot End Plate

[Dee Smith]

I am assembling my 8" i3v and find that there is a gap between the bottom of the extruder and the top of the aluminum plate that holds the top of the Hexagon hot end. It appears that the top of the hot end cannot go into the recess in the bottom of the extruder far enough by about .75mm. This creates the gap.

My question is do I need to remove some material from the bottom of the recess to make it deeper or is this ok as it is? I think I need to make it deeper. Does a gap between the extruder and the top of the hot end matter if I rout out too much material? Once I bolt everything together with the extruder/hot end and the x axis carriage, I think everything should be snug and not have any gaps but not put any unnecessary strain on the components.

Thanks for any advice you can give me,

Dee

[gmay3]

Hi Dee,

I'd like to hear the opinions from the others, but I think I would agree with what you said about removing the material so the top of the hot end fits into the bottom of the extruder without leaving a gap.

I think I used just a normal x-acto knife to remove just a few layers to clean out this area.

[printbus]

How do you have the aluminum plate oriented? I was confused by that, and initially had it upside down and rotated 180 degrees from what I now think is the right way to have it. Having the groove on the U on the bottom vs the top would raise up the hot end some and possibly be your problem. If that's already right, I agree on cleaning out enough material to get the extruder base sitting flat on the carriage.

On my newly printed base, I had the opposite problem and added a few pieces of kapton tape on the top end of the hot end... I wonder how consistent the aluminum plates and hot ends are. My Hex hot end and aluminum plate don't fit together tight at all - I shim the channel with kapton tape to tighten things up.

[clough42]

The parts should fit together without a gap. Try flipping the plate so the rabbit is on the top, if you have it on the bottom.

Check the recess to be sure it's clean and doesn't have some stray lumps or other artifacts from the printing process. I could see you maybe needing to clean out the corners if they're rounded, but I would not expect you to have to remove whole layers of plastic, unless something went terribly wrong during printing.

Ideally, there should be a tiny gap that closes when you tighten the screws. This pre-loads the top of the hot end and clamps it against the plate. This pressure prevents the hot end from rocking or turning while printing.

[Dee Smith]

Kevin, I think you nailed it. I went out to the garage and checked it out and sure enough, the plate was upside down. When I turned it over, the gap disappeared except for a hairline gap which should close up when I bolt it up. It should keep the hot end nice and stable now. I had replayed the assembly videos over and over trying to determine which side was correct but came up with the wrong side anyway.

Thanks for your help,

Dee

[printbus]

...I had replayed the assembly videos over and over trying to determine which side was correct but came up with the wrong side anyway.

Been there, done that! Enjoy the rest of your build.

[Dee Smith]

Thanks,

Dee