Alternative slimmer shim

[luciancd]

I tried out the shim yesterday with Verbatim PLA, because i had problems removing the PLA without the shim.

The first shim print went south because the raft did not stick to the bed very well.
The resulting distance is too high in my opinion. I think 0.3mm would be better distance, at least with my Verbatim PLA.

Do you know something in common households that could be suited as an slimmer shim ?

[z-renegade]

Verbatim PLA is special. Some spools require a shim, some not. I didn't find a rule yet.
In other words: You have to test the correct shim height.

Best to use is a feeler gauge like this: https://en.wikipedia.org/wiki/Feeler_gauge

This one can be disassembled and one has many different heights available.

Bed level is also something that has to be watched BTW!
I bought two V2 perf boards lately, that tend to lift in the middle.
That way the bed varies by 0.3 from the center to the outer edges.
If your print consumes large raft area on such a bed and you use a shim to further lift the nozzle, you're on the loose.

[luciancd]

thank you, did not know a feeler gauge thingi existed !

i will try to buy one !

[luciancd]

i made my own 0.25mm shim using copperfoil i had from a previous project.
aluminiumfoil should also work.

the first time i used the z-temp shim my nozzle crashed into the build plate. i anticipated that
so i turned the printer off immediately.

the risk of crashing the nozzle using a foil could be lesser because of the softness of the foil.

[Julia Truchsess]

Contact through the included brass shim can be improved by cutting some rough "crosshatch" lines on both sides with a knife or scraper. The rough edges of the gouged lines will help cut through glue stick, residual plastic, contact oxidation, etc.

[luciancd]

I scratched the shim after the crash and it worked after that.

Thx

[Cicio]

I I clean it with the spray for electrical contacts, both the shim and plate

[Cicio]

I tried the thickness gauges for mechanical, they are metallic and conductive, but do not work, surely the electrical resistance is different

[z-renegade]

I I clean it with the spray for electrical contacts, both the shim and plate

This does not solve the issue, I never heard about someone cleaning plate and nozzle like that when printing without a shim.

I tried the thickness gauges for mechanical, they are metallic and conductive, but do not work, surely the electrical resistance is different

Maybe a translation issue, but the difference in electrical resistance between different metallic shims (different height/metal) is IMO not even measurable to the sensing circuit since the wiring resistances tolerance is even higher.

It's about contact resistance, Julia showed a mechanical way to optimize this.
I use the following setup for non conductive beds, it ensures an optimal shim to bed connection.

[Cicio]

I was referring to the fact of the thickness cleaning, not the problem that you expressed you;)
I have to try again, but for now the only result was to scratch the plate with the nozzle after using different thickness than the Z-temp

[z-renegade]

Look at that nice perf board 

I always keep the outer edges of the contacts (and center of the middle contact) clean.
They do not have to be treated, the outer ones cannot be printed on, the center (at a 2cm diameter circle) does not need to be treated.

Anyway, I would not use this perf board with a shim, except if it is wired like shown on my previous post.

The reason is, that the shim covers the treated (dirty and a bit higher) areas of the perf board also what makes it lifted in the center, having no contact to the metal area of the center. The nozzle has to bend it down to that area what get's harder if the shim is thicker and allows only for a small area to be touched. If that area is a even a hole of the perf board it's getting even harder.

When using a shim (that is when printing PLA and other filaments that swell) I use an untreated perf board (no slurry, no glue, whatever...).
I instead vary the bed temp (aprox. 30, 42, 55 degrees centigrade with the new Z-Temp bed switch).

If you want or have to use a treated/non conductive bed, consider the setup of my last post.

[luciancd]

z-renegade thank you for the pictures, very interesting setup !
is the perforated board even needed in your first pic ?
 

[z-renegade]

Of course you could leave the perf board off but then have to adapt (electrically and mechanically) the connection from the shim to the cable that is connected to the perf boards connector.

I had no mood/need to do that, just used an old V1 perf board.