Author Topic: Need Machinist to make a Pellet Swager (Read 19432 times - 2 votes)
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ken47 · « **Reply #80 on:** July 28, 2018, 10:58:50 AM »

Subscriber, that's a terrific cost effective solution. I have both the Arduino and the geared motor along with its drive. This is gonna be my next project after completing EDM sinking sideways. I am thinking of automating the self centering vise or chuck using a IP67 servo motor. The pic of EDM tool (I removed it from the forum, obvious reasons, anyways PM me if anyone wants a pic)

Wayne52 · « **Reply #81 on:** July 28, 2018, 05:05:17 PM »

I would probably go over to the shop and talk to the owner myself, he's a friend, he lets us (my brother has keys to the place) use his shop. My brother is a retired journeyman mold maker himself.

Wayne52 · « **Reply #82 on:** July 28, 2018, 05:10:08 PM »

Ken can you burn a lot of cavities with just the one electrode you make? I personally don't know much about them, my brother has talked about them quite a bit though.

subscriber · « **Reply #83 on:** July 28, 2018, 08:30:47 PM »

Electrode VS job erosion rates, and surface finish achieved at different current settings and pulse duration:

http://iopscience.iop.org/article/10.1088/1757-899X/50/1/012062/pdf

Designing electrodes. Including compensation for "over-burn" (hole larger than electrode):

https://www.theseus.fi/bitstream/handle/10024/86204/Thesis-Bishwas.pdf?sequence=1

ken47 · « **Reply #84 on:** July 29, 2018, 03:54:12 AM »

Wayne, The tool wear gets accelerated over series of operations, hence a set of identical tools have to be made (that's what the EDM technician said), So I have made a total of 12 tools where 6 have a .XY offset to compensate for erosion and other 6 have .XZ offset. Sub. Thanks for the research papers, I’m humbled and appreciative for all you’ve done. Tomorrow I will get things tried and tested on EDM.

subscriber · « **Reply #85 on:** July 29, 2018, 04:37:54 AM »

Ken. Only too glad, if I can be of any help.

Exact diameter and roundness of the pellet heads and skirts are the most important aspects. As such, it would seem to me that those aspects should be "burnt" to finished dimensions, last. That way, the last electrodes you use will already have clearance with the cavities in the less important dimensions.

Based on the papers I linked, finishing should be done at lower current, to achieve a smoother finish, and to slow electrode erosion to produce a more exact cavity.

That said, my goal is only to provide food for thought. An experienced EDM guy should know the answer to all these questions; or should know how to determine them.

darkcharisma · « **Reply #86 on:** July 29, 2018, 03:16:42 PM »

Sub. you mention you want your owm edm machine. i am sure you can get online and find some used one as a base to work with. they are currently under 10k

subscriber · « **Reply #87 on:** August 01, 2018, 04:50:01 AM »

Quote from: darkcharisma on July 29, 2018, 03:16:42 PM

Sub. you mention you want your owm edm machine. i am sure you can get online and find some used one as a base to work with. they are currently under 10k

I'll take two

Ken has been quiet. Either he is very busy; or he has stopped...

ken47 · « **Reply #88 on:** August 01, 2018, 10:46:26 AM »

I was figuring out what went wrong on first attempt. Though the pellets were perfect round head diabolo but the head diameter was not upto the mark. I revisited my EDM technician and figured out the size for rough pass and Final finish. I tested with a 5.40 mm tool and got 5.403mm cavity on the correct current, Now I know what it takes to make a perfect 5.50mm-5.51mm-5.52mm heads. Tomorrow I will try to score the perfect Home run with a 5.5XYZ mm head. Thanks sub. the research papers helped.

By friday I will work on .25 and .22 moulds. Will keep on posting about the progress from Friday, so tomorrow I will be busy making blueprints and CAM co-ordinates for drilling some guide holes.

AmBraCol · « **Reply #89 on:** August 02, 2018, 09:51:19 AM »

This has been an interesting thread to follow. Looking forward to seeing how this pans out, Ken!

darkcharisma · « **Reply #90 on:** August 02, 2018, 06:29:55 PM »

Quote

I'll take two

Ken has been quiet. Either he is very busy; or he has stopped...

I wish i'd know everything about CAD and EDM, i'd jump at some deals on ebay even...i might even settle for manual instead of CNC EDM...lol EDM on ebay is dirt cheap.

Ken, i know you been busy. don't forget to update us on Friday

Wayne52 · « **Reply #91 on:** August 02, 2018, 06:56:15 PM »

That's definitely some very cool stuff you going on there Ken!!! Every time I see a new post on this thread I'm right on it.

ken47 · « **Reply #92 on:** August 03, 2018, 04:03:55 AM »

Friday update: Tool steel from Germany has arrived. It will form the mould core. Right now its getting machined (Milling and surface grinding). as of now I am making 2 versions now in .25 caliber. a custom slug 50 grains and a 40...ish grain .417" long round head diabolo. I managed to make .22 in 5.52mm head but the test material (S.S.) was fighting back because its not magnetic and EDM tool simply wears out due to arcing making other 4 cavities smaller and smaller. So .25 is bigger and new material is perfectly suited for EDM operations. making 2 moulds in a shift saves $$ and time.

Other thing. as Sub. said EDM makes grainy texture, I couldn't find a polishing process that will guarantee me "Consistent" MRR for smooth finish. It wont be any problem for swaging, but it will be of some issue with casting. (which is not a swager is intended to be). I will get around the .22 but with 30-32 grain design that fits most of the mags.

subscriber · « **Reply #93 on:** August 03, 2018, 04:36:24 AM »

Ken, if the texture is fine enough, think of it as engineered to hold just the right amount of lube.

If the finish is too rough, both swaged and cast pellets may battle to come out of the mold half, requiring so much persuasion that they may get some marks on the pellets.

Remember, reducing the current improves surface finish, because each micro pit burnt is smaller. You might try that on your finishing burns. One of those papers gave comparative current and time values.

ken47 · « **Reply #94 on:** August 03, 2018, 05:43:12 AM »

Sub. I got it. the machine here is slightly different so some tweaks in settings will be just fine to produce fine and even grainy texture.

ken47 · « **Reply #95 on:** August 04, 2018, 01:31:55 PM »

Saturday update:

1. Milling and sizing of block's is complete.
2. Blocks have been drilled and will be ready for EDM by Tuesday.
3. New .25 punch are getting ready ETA Monday
Things are going slow and steady,I double check every step to assure that errors in previous attempts don't repeat this time.

Estimated time of completion will be somewhere on Wednesday or Thursday.

subscriber · « **Reply #96 on:** August 04, 2018, 09:26:57 PM »

Thanks for the update , Ken.

What kind of steel are the blocks? In what conditions / hardness?

ken47 · « **Reply #97 on:** August 07, 2018, 11:45:39 AM »

Hello, Ive been busy scrambling all my resources to make the tool steel swaging Die (its not a mould Now). The block is partially machined and is ready for hardening before going EDM. Tomorrow the remaining machining process will get completed especially reaming the guide holes to match the parting lines. Other ancillary parts like punch and guide plate is getting machined as I write this update, So far so good.

darkcharisma · « **Reply #98 on:** August 07, 2018, 03:49:08 PM »

Looks good Ken.

Sub, I think he's working on some german alloy steel. I have not been able to get a the exact name but somewhere around A2 composition. P20 is a good start or even better with S7. But steel grades in other parts of the worlds are also different. I have been working one swaging dies with o1 steel and i like it.

subscriber · « **Reply #99 on:** August 07, 2018, 10:21:19 PM »

Looking good, Ken!

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Need Machinist to make a Pellet Swager

Author Topic: Need Machinist to make a Pellet Swager (Read 19432 times - 2 votes) )

Author Topic: Need Machinist to make a Pellet Swager (Read 19432 times - 2 votes)
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