A simple self acting spark erosion machine.

[Andrew TinsleyParticipant @andrewtinsley63637]

The above was an article by Derek Lynas, in the Stockport ME website. I can access the written word, but all of the diagrams etc are not visible. Are any of you Google experts able to track down the missing bits.

It sounds  as if it could be a decent metal remover at a 50 V working rating. I am in need of a simple quick to build system to cover up a nasty which I have managed to do. Other simple systems that are on the web are not exactly fire eaters unless they are modified and made more complex.

Regards,

Andrew.

 

[Grindstone CowboyParticipant @grindstonecowboy]

Try this, top result on Google.

 

Links to https://uploads.tapatalk-cdn.com/files-3254/1715863563_SparkEroder.pdf

 

Rob

[Michael GilliganParticipant @michaelgilligan61133]

Well found, Rob

… I look forward to reading of Andrew’s success

MichaelG.

[JasonBModerator @jasonb]

I would think contacting the email on the top of the pdf would be the best place to find out where the drawings can be had. Article only says they are available but not from where!

[Michael GilliganParticipant @michaelgilligan61133]

Am I going daft, Jason ?

Does the download linked by Rob not include all of the drawings that one might reasonably require?

MichaelG.

[JasonBModerator @jasonb]

Not you are not daft. My first Google result was a 2 page pdf with just text so I thought rods link was the same and did not follow it

[Michael GilliganParticipant @michaelgilligan61133]

< phew >

[Michael Gilligan]

On Michael Gilligan Said:

Am I going daft, Jason ?

Does the download linked by Rob not include all of the drawings that one might reasonably require?

MichaelG.

i hope so. i have just put this on top of my todo list. i will be using it under paraffin

[BazyleParticipant @bazyle]

Rob’s link worked for me with pictures. I think this was demonstrated at a ME show quite a few years ago when it was at the racecourse on the SME stand and they were selling a single A4 plan for about 50p. I must have got it somewhere.

[Andrew TinsleyParticipant @andrewtinsley63637]

Thanks Rob,

Despite many variations of the search terms, I could only find the two page written description. I must admit that I am not too good at Googling

I will be getting on with this over the next day or two, I will report back when it is working.

Thanks everyone,

Andrew.

[noel shelleyParticipant @noelshelley55608]

A ball bearing drawer slide will make a simple mounting to give the vertical movement. Paraffin will work as an electrolyte but the costings are well out of date. A higher voltage and current will speed things up but no control of the spark gap as it cuts will make things slow ! I redesigned one of the published units to use 100v at 3A or 66v at 8A using a pair of one arm bandit transformers. The power resistor was part of an electric fire element at 10 Ohms. Automatic Height control made this a very useful tool. Good luck. Noel.

[Grindstone CowboyParticipant @grindstonecowboy]

Just had a look at the rest of the results of the search and found these modifications which may be of interest.

 

Links to http://mikesworkshop.weebly.com/a-spark-erosion-apparatus.html

 

Rob

[Andrew TinsleyParticipant @andrewtinsley63637]

It was the Mike’s workshop article that put me onto the Derek Lynas design. In my simple minded way, I thought the Mike’s workshop design a somewhat retrograde step. Although very simple to implement. I am a firm believer in the more volts the better school of thought.

As an aside, I am puzzled by the use of the term electrolyte. As far as I can see, it has nothing to do with electrolysis. I think its use is simply to reduce the oxidation if the process were done in air. But happy to be shown that I am wrong!

Andrew.

[Michael GilliganParticipant @michaelgilligan61133]

Please forgive me if I am quoting the wrong line, Andrew … but

”dielectric fluid” is not the same as “electrolyte”

MichaelG.

Quote:

During use the work and the tool are submerged in a bath of dielectric fluid. Distilled water or kerosene are commonly used.

[NealebParticipant @nealeb]

Not just to avoid oxidation. The fluid plays a useful role in the cutting process. As the spark occurs, you generate extremely high temperatures in its immediate region which explosively boils a tiny volume of the fluid. It’s not clear to me if this generates a cavitation effect that helps material removal, but it does help disperse the material boiled off the workpiece itself; without this, the spark gap tends to fill with condensed solid material that is the “swarf” from the cutting. For the same reason, it helps if you can keep the fluid moving in the region of the cut although it will work without this.

I have demonstrated the SMEE wire EDM machine at a number of exhibitions over the years and one of our problems was in the fluid handling. The simple sinker-type machine discussed above is not so fussy but when you get into wire eroding, flushing the cutting area with clean, low-conductivity fluid is critical. We used deionised water but because it was designed for “up close and personal” demonstrations, we could never use as powerful a jet directed at the cut as the process demanded. The fluid was filtered, passed through a deioniser, and recirculated. We used water as a dielectric.

[noel shelleyParticipant @noelshelley55608]

Careless use of incorrect terminology ! Should be dielectric fluid. Noel.

[Andrew TinsleyParticipant @andrewtinsley63637]

Hello Michael,

Most articles in the model engineering press that deal with spark erosion, refer to electrolyte rather than dielectric fluid. As Noel points out, it is a careless use of incorrect terminology.

For these simple set ups, the dispersion of debris is really a non issue, quite unlike the professional set ups where the debris becomes a real problem because of the high removal rates.

Andrew.

[Michael GilliganParticipant @michaelgilligan61133]

That was exactly my point, Andrew … [although I had wrongly assumed it to be your mis-reading].

I think “Most articles in the model engineering press” are riddled with such errors and sloppy usage … but when I mention it here the general reaction seems to be “language evolves” or “everyone here knows what it means”.

MichaelG.

[ChrisLHParticipant @chrislh]

In response to Michael’s last sentence above and feeling slightly grumpy, a common example of sloppy and even misleading usage is “ball bearing” for what is, it turns out, a steel ball. Sometimes it’s obvious particularly if an illustration is provided but at other times I can be imagining a thing with inner race, outer race, balls and cage when nothing of the sort is intended. But as you say “everyone here (except me) knows what it means”.

[NealebParticipant @nealeb]

Surely a drawer slide is an infinite radius circular ball bearing, complete with inner and outer races? Albeit a rather low-precision bearing…

[noel shelleyParticipant @noelshelley55608]

A draw slide is ideal for this application and might be better described as a linear bearing ? Noel.

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