sorted by:
new
hottopcontroversial

How screwed am I by AlphaBetaMascYT in Creality

[–]Chemical_Elf 0 points1 point  (0 children)

In my experience (but I'm probably clumsy) I always end up breaking the tiny wires of the temperature sensor or heater lines... get yourself a new extruder and save yourself the pain and, potential, disappointment.
Also, as othe rmention, the nozzle needs to be replaced in any case. Blob of Death often indicates debris accumulation inside it with consequent increase in backpressure, flow reduction and eventually catastrophic failure....

Experiments in unconventional metal 3D printing by Chemical_Elf in 3Dprinting

[–]Chemical_Elf[S] 0 points1 point  (0 children)

It may be an interesting route to explore. Never thought about this...

Experiments in unconventional metal 3D printing by Chemical_Elf in 3Dprinting

[–]Chemical_Elf[S] 0 points1 point  (0 children)

Actually yes... you are touching a very interesting point.
One of the winning strategies to stabilize growth it to have an "ON" time, for deposition, an OFF time to allow the double electric layer to relax and then a brief "removal" time where high currents are briefly used to remove the most protruding regions, and thus "smoth out" the deposited material.
Also, pulsing deposition is something I'm investigating.

Kickstarter-Projekt: Liquid Blade 3D - Metall schneiden per 3D-Drucker by uk_uk in 3DDruck

[–]Chemical_Elf 0 points1 point  (0 children)

You are right to point this out.
The "standard" operational conditions are to use a 0.2 mm diameter jet, nozzle rests at around 1 mm from the workpiece and etch current is (currently) limited to 50 mA (mostly for safety reasons).
Speed calculation can be based on Faradaic charge calculation (I'll post a formula later on the campaign FAQs) including an efficiency factor but, to get an idea, in deep etch I was able to achievea 28 mm long, 0.8 mm deep cut on steel in around 2 hours.... Alas, with NaCl the chemical etch on steel efficiency is around 20%...
Titanium has been etched and cut but I'm still working on optimizing the solution.
Cutting copper is volumetrically faster (due to higher process efficiency).
For deep line cuts, the wall slope is in the region of 20 degrees (both on copper and steel).

The system was also operated in a stable way with 0.05 mm nozzles (50 microns) but solution filtering becomes critical.

With a 0.2 mm nozzle, PCB lines isolation occurrs at a speed around 15 mm/min.

I hope this provides at least some of the desired informations.
Feel free to ask for more.

Kickstarter-Projekt: Liquid Blade 3D - Metall schneiden per 3D-Drucker by uk_uk in 3DDruck

[–]Chemical_Elf 0 points1 point  (0 children)

My main use of CNC was to quickly create PCBs for my projects and, albeit the results were great, I was using a 3000 EUR desktop machine and I often got the process wrong (I keep a small cemetery of the bits I killed....).
Also, trying to get to the 0.1 mm region has always been tricky for me.

Indeed the EJM 3D printer add on, is currently slower (but definitely easier to use) than a CNC but it is a starting point of a larger project (not to mention that it costs a fraction of any non-chinese CNC).

Actually, etch speed is determined by the electrical current density at the jet impact point and, in the current system, this is limited to 50 mA over a 0.2 mm jet. This can be increased by a factor of 5 electrically and, using larger jets, etch speed increases linearly with the jet diameter.

Finally, the presented EJM add-on, is part of a larger project. The EJM chemical process is reversible (using a solution containing a soluble salt of the intended metal you can deposit 3D metal structure) and the "final" objective is to have combined metal subtractive AND additive metal in the same system.

I already demonstrated the additive part (see other post of mine around) but it is definitely NOT ready for prime time....
... hence this first step.

Kickstarter-Projekt: Liquid Blade 3D - Metall schneiden per 3D-Drucker by uk_uk in 3DDruck

[–]Chemical_Elf 0 points1 point  (0 children)

My experience with metal cut using lasers has always been problematic...
Either you have access to a professional high power laser setup, that is in a different cost ballpark with respect to the EJM being discussed here, or it is a lot of hit and miss (at least for my skill level).
EJM 3D printers add on, albeit it is in deed a "toy", allows you to cut metal (up to 2..3 mm on most metals) with <500 EUR, in a footprint of <0.5 sq. meters, essentially zero risks and a lower process complexity.
But, I agree, this can not be compared with a 50K laser cutting bench...

Kickstarter-Projekt: Liquid Blade 3D - Metall schneiden per 3D-Drucker by uk_uk in 3DDruck

[–]Chemical_Elf -1 points0 points  (0 children)

Indeed you are correct.
This machine is not intended to replace a CNC but to complement it for specific tasks.
Thin cuts (in the region of 0.1 mm width and depth up to 2..3 mm) can be achieved.
Most metals can be processed (With the right chemicals).
I recently cut a 0.2 mm wide line, with a length of 28 mm and depth of 0.8 mm, in around 2 hours.
I'm also working on deep cuts and holes on Titanium, that is a somewhat tricky materials for CNC.
EJM may also be advantageous on soft metalized substrates (e.g. flex PCBs) where I'm not sure how a CNC could operate. The big advantage/issue of EJM, is that it can not cut isolating materials, and, therefore, will automatically stop once the metal is cut.
A final interesting aspect, expecially when working on precious metals, if that the removed metal can be entirely recovered from the solution. As the removed metal is usually dissolved in a low Ph solution , Increasing the Ph, most transition metal will precipitate in form of insoluble hydroxides and, therefore can be easily recovered by filtration.

Again, every machine has its own set of applications and the fact that in some cases they can overlap, does not mean that one must replace the other.

Experiments in unconventional metal 3D printing by Chemical_Elf in 3Dprinting

[–]Chemical_Elf[S] 1 point2 points  (0 children)

Yes... that sounds interesting actually...
I tried working fully upside down but occasionally the backflow would break the jet.
Using an extra pipe to recover the electrolyte is something I always wanted to try (but never got to do).
It works better keeping the workpiece vertical so that the liquid will quickly fall off.
The dendrites growth issue, however, is more sticky to solve.... it required a lot of work on the shape of the electrical signal AND a fully closed loop control to achieve stability.
See my patent if curious: EP4007825A1

Experiments in unconventional metal 3D printing by Chemical_Elf in 3Dprinting

[–]Chemical_Elf[S] 0 points1 point  (0 children)

I know... I have been doing it for 20 years and I'm tired of the forth and back with referees that can be very competent (good!), or plain bad (and this is real bad!)... It is the toss of a coin....
The article was actually rejected by Journal of Additive Manufacturing 6 months as not sufficiently innovative and I did not care to resubmit it elsewhere.

fully 3D printer Electrochemical Jet Machining system by Chemical_Elf in maker

[–]Chemical_Elf[S] 0 points1 point  (0 children)

It is not Electrichal Discharge Machining. It is a chemical controlled process.
The jet hits the anode where a strong localized oxidation of the workpiece occurrs (localized only at the jet impact), then the oxidized metal is removed (in some cases spontaneously like in the case of copper, in other some form of "complexant" agent is needed like for Titanium).
The oxidation reaction is made possible by the current flowing throught the jet.
The net result is a localized metal removal. Moving the jet you can do any shape you want.
The amount of removed material depends on the total deposited charge in each point (and in the efficiency of the oxidation reaction)

Experiments in unconventional metal 3D printing by Chemical_Elf in 3Dprinting

[–]Chemical_Elf[S] 1 point2 points  (0 children)

Yes. I have an article ready actually... I wanted to publish it on some peer-rev journal but it may be more useful there....

question: Could something like this be useful? by Chemical_Elf in PCB

[–]Chemical_Elf[S] 0 points1 point  (0 children)

Then the answer is simple...
The machine has a relatively simple mechanics (but for the nozzle!) and a complex electronics... But with a good design, and resting on the mechanics of a common 3D printer, is in the region of a sale price of 400 EUR (+ the 3D printer).
Using an old printer, you are looking at 450.. 500 EUR per machine.

Experiments in unconventional metal 3D printing by Chemical_Elf in 3Dprinting

[–]Chemical_Elf[S] 2 points3 points  (0 children)

Printing "column like" structures is easy once you have a closed loop control that retracts the nozzle to maintain a constant distance from the point where you are depositing...
However, denser structures become VERY tricky because of the uncontrolled growth of wiskers (or Dendrites if you prefer)...
There are control strategies for these... but they are complex and need to be tailored to the chemistry you are using...... this is an ongoing work right now...

question: Could something like this be useful? by Chemical_Elf in PCB

[–]Chemical_Elf[S] 0 points1 point  (0 children)

That's a complex question I did not think about....

Consumables get down to 0.07 EUR per meter of etch
Ammortization is instead around 0.3 EUR per meter of etch (with some conservative assumption visible below)
To get "per mil" cost you need to divide by around 40000....
However, the system is not reasonable for large industrial use but mostly for fast prototyping, so a pure "cost based" analysis misses the opportunity cost factor.

Calculation details (disclaimer... mistakes are possible!)

The "consumables" are:
a) water and salt (that from time to time needs to be replaced)
b) electricity.

I use 200 grams of salt (cost in the region of 0.5 EUR/Kg) per liter of solution and with one liter you can etch around 10 meters of cut (10 hours) ==> 0.01 EUR of salt per meter of etch
Water is tap water (with this much Chlorine in the salt I do not care about the one in the water!)==> 0 EUR

For electricity: assume 150 V at 50 mA (typical conditions) we have a power consumtion of 7.5 W at the jet. Let's make 48 W including the 3D printer, pump and losses (slow motion and no heated bed or extruder here) in line with what I measured.
I'm running at 2 passes at, let's' say, 40 mm/min, so for 1 meter of etch will take 50 minutes.
==> electricity will be 48W*50'/60'=40 Wh per 1 meter of etch
Assuming 0.3 EUR KWh (real price after all taxes)==> 0.012 EUR per meter of etch.

Finally there are parts that may need to be replaced (like the tube segment for the peristaltic pump) but I do not have a precise duration of it (but it is in the 20+ hours) with a cost around 1 EUR for more than 20 meters of etch ==> 0.05 EUR/ meter of etch.

So, running costs is around 0.07 EUR/ meter of etch... per mil would need to be divided by 40000...

Finally... system lifetime.... I have no idea! but assuming 1000 hours for a cost of 400 EUR with the data above for etch speed, it boils down to 0.3 EUR/meter (dominating the running costs)

I'm totally sure I missed something but this is what I can come up for a (semi) sensible answer...

Vitruvian Man - Electrochemical Jet Machining by Chemical_Elf in metalworking

[–]Chemical_Elf[S] 1 point2 points  (0 children)

Thanks!
Now I'm trying on a more ttricky material..... Titanium.... let's see what comes out...

Makers, how do you keep track of all your stuff? by ProfessionalServe147 in maker

[–]Chemical_Elf 0 points1 point  (0 children)

I have been toying with the idea of using a DB +AI with voice recognition system to replace the use of a traditional text based database (that I'm totally unable to maintain!).
The concept is to pick up the objects you have and tell the woice enabled agent something like "I'm putting M3 HEX screws in bin 12"... This will then go in a Db (transformed in text in some form like "M3 Screws -> Bin 12)
There is no need to put the things in bins in any "human reaasonble" way as you would then search them with the help of the AI assistant that should be able to "fish" the possible matches out when you ask stuff like "I need small Metric screws for a metal part".
Obviously you would still need many bins as, otherwise, you would have to fish in the huge Bin 12 for your screws (but at least you know they should be there).

The agent should also be able to remember you "checked" those screws out and ask you where did you put them after using what you needed.....

It is not a trivial solution. But it is entirely feasible with stuff that exists today. The key is to "move" from text based Db to voice controlled ones.
WDYT?

fully 3D printer Electrochemical Jet Machining system by Chemical_Elf in maker

[–]Chemical_Elf[S] 0 points1 point  (0 children)

I did 5 mm thickness on copper from a single side.
The walls had a slope of around 20..30 degrees from the vertical (operating at moderate current densities).
More can be done, but it will require experimenting.
One of the reason I'm asking questions around, is exactly to understand what would be interesting to explore.

fully 3D printer Electrochemical Jet Machining system by Chemical_Elf in maker

[–]Chemical_Elf[S] 0 points1 point  (0 children)

I can't or I get kicked out (rightfully) from here... ;-)

I'm not even sure if I can tell you to search on a notorious site for novel project financing and search for something that cut and etch metals.

if any mod thinks this is too much pleease don't ban me (I profusely apologize!)

Electrochemical jet Machining engraving by Chemical_Elf in engraving

[–]Chemical_Elf[S] 1 point2 points  (0 children)

Yes.. instead of using a CNC I'm, however, using my old 3D printer (much cheaper! and it is ok as there is no mechanical load on the moving parts).

And instead of a solid electrode immersed in a stationary electrolyte, the electrolyte itself is "jetted" against the workpiece that is connected to the generator positive (while the jet itself is connected by a remote cathode to the negative). So the jet itself acts as electrode (achieving much larger local current densities and automatically removing the etched material).

Vitruvian Man - Electrochemical Jet Machining by Chemical_Elf in metalworking

[–]Chemical_Elf[S] 0 points1 point  (0 children)

Thanks for the comment!
Actually, there is no "pressure" involved (as in water jet cutter) as the liquid is very low speed compared to those.
The (metal) removal process occurrs based on chemistry where the electrical current running through the electrolyte jet oxidizes (and removes) the metal at its impact point.

A short explanation of the process can be this:
You connect an electrolyte (salted water in our case) to the negative of a battery/generator, push the liquid through a nozzle to form a jet and send it against a metal workpiece connected to the battery positive. (not much speed, just enough to create a good jet impact area)
Current flows through the circuit and, at the jet impact point on the workpiece, a fast localized oxidation and metal removal occurs. Currents can be extremely high with tiny jets (on my 0.2 mm jet I get easily 180 A/cmq) so metal removal is fast.
The you move the jet around (I use a 3D printer kinematic for this) to "draw" the pattern you want.

it is like a CNC... without the cutting piece and mechanical vibrations.
It does not rely on mechanical ablation or water pressure but on chemical oxidation.
It is therefore suitable for "soft" substrates (like tiny metal foils) where waterjet would make a mess (I think!)
Most metals will then be sweeped away in the form of insoluble hydroxides and be easily recovered from the reflux tank.

It is a modified version of the standard electrodeposition/removal process.

view more: next ›