CNC brass engraving from an stl file

Hi there,

I'm a little lady in London. I'm a professional modelmaker and metalwork enthusiast. I've also got myself into a bit of a catch 22 situation...

For the past few months I've been sculpting some detailed brass mould inserts with a view to 3d engraving them on a milling machine I have access to. They are approximately 100mm x 80mm x 12mm each and there are 12 of them.

As they are scupltures they are in the form of stl files. I've just found out that not only does the milling machine only work from IGES files, but it's also not fast enough to do the engraving.

The stl file is too detailed to convert to IGES, so I'm hoping to find someone who would be in a position to engrave the inserts with a cnc router/ engraver.

As I was planning on doing this myself I didn't really have a budget for it, so I can only put together a few hundred pounds.

It's a really interesting project so I really want to finish it. Any help or advice would be very much appreciated.

Hello Little Lady.!!. . . . Lets see the files to see how detailed.?

Creep.............

Careful he owns a brown mac too......

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Originally Posted by 2e0poz

Careful he owns a brown mac too......

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No but I do have brown stained overall if that does it for ya.!! .:love_heart:

LOL!...Always knew he was scary

OO he's a right smooth talker

Hello Boys!

I know it's not everyday you come across a woman who knows what to do with a wobbler, but let's try to stick to the engraving shall we ;-)

The mould is basically for some little characters I've sculpted. Mr Jazzycnc, I'll send you a PM of what it looks like as I feel a bit akward about displaying my own artwork. Because of the way I've created the figures the mould looks very detailed, but I don't expect to machine such a high level of detail. I've got a little sample mould file of a small bit of it and I'm hoping someone can do a test for me and run an engraving bit over it.

It seems like a fairly straightforward thing to do, but you wouldn't believe how difficult it's been to find someone to do it.

If someone is prepared to try it for me I could offer cash or my modelmaking services in exchange...PM me for details.

Thanks you!

Update: A couple of people have very kindly offered to look at my files, which I'll send in a mo. We'll see how we go with producing a sample and I'll post an update to follow up.

I'm truely touched by people's friendliness :-)

Well, time has passed and I've finally finished my 3d relief files. As always, 3d drawing takes longer than you think....

Unfortunately, the couple of people who contacted me before have been unable to help so I'm throwing it back out there.

If anyone has the capability to 3d engrave brass/aluminium from an stl file then please do get in touch. I have the files and cash waiting and would even be prepared to go into partnership with someone with the necessary facilities.

Fingers crossed (again!)

Pm me the files and i'll take a look. i might be able to do something depending on how complex

Thanks John, file is in the electronic post to you.

If you are talking 3D engraving without over hangs (I don't currently have a 4th axis) I should be able to help you. If you are talking of needing a 4th axis, that is a different kettle of fish. Gladly do a test run for you in acrylic to see what we are looking at finish wise.

Michael

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Originally Posted by m.marino

If you are talking 3D engraving without over hangs (I don't currently have a 4th axis) I should be able to help you. If you are talking of needing a 4th axis, that is a different kettle of fish. Gladly do a test run for you in acrylic to see what we are looking at finish wise.

Michael

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Well you'll be a better man than I gunga din if you can. . .Lol

Got to ask , whats so difficult about the file?

If milling isn`t an option can it return to its STL roots and look at a 3d printing process?

And how do you avoid creating a file so complex that Jazz won`t attempt it ? :-)

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Originally Posted by Musht

And how do you avoid creating a file so complex that Jazz won`t attempt it ? :-)

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How can I possibly resist ... if you send it to me I'll have a go.

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Originally Posted by Musht

Got to ask , whats so difficult about the file?

If milling isn`t an option can it return to its STL roots and look at a 3d printing process?

And how do you avoid creating a file so complex that Jazz won`t attempt it ? :-)

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It's do able but far too much detail will be lost IMO that the result won't be acceptable and it's a lot of work and time to find out.??

Hi guys,

Micheal, Jonathan, I've sent you a request for an email address so I can send you a file.
Musht, The little characters of mine are quite detailed so it's going to take a while to machine the inserts. Unfortunately 3d printing isn't an option :-(

Hey MrJazz, did you get the mini mould test sample file I sent you, the one with just the 3 figures on? What would you want from me to machine that beauty? Please don't worry about the 'faceting' on the background surface, it's meant to be like that. I know this project is a challenge, but how dull would life be if we didn't try something new every now and again?! Also, bear in mind that I'm not asking anyone to give their time fro free and If you only knew what it was for you'd bite my hand off at the chance to become a partner! :smile:

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Originally Posted by Statstastic

Hi guys,

Micheal, Jonathan, I've sent you a request for an email address so I can send you a file.
Musht, The little characters of mine are quite detailed so it's going to take a while to machine the inserts. Unfortunately 3d printing isn't an option :-(

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You probably already know, but you can get things printed in metal. Even gold plated! I have been meaning to try out one of the services when I find the right object...

I have making candle holders in plastic, I am told that is a "fire risk"- would be better in metal or ceramic.

Hi Bob,
I'm inclined to agree that a plastic candle holder may be a fire risk!

DMLS sure is amazing. Ultimately though, it's a composite, so I wouldn't be sure of it's structural integrity for moulding purposes - particularly under pressure. Also, it's still very expensive, so it would be a costly way to find out that it definitely can't be used. Machined metal moulds on the other hand, are a tried and tested technique.

Good idea though.

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Originally Posted by Statstastic

Hey MrJazz, did you get the mini mould test sample file I sent you, the one with just the 3 figures on? What would you want from me to machine that beauty?

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Hi S,

Yes got it and thats relatively easy just will be time consuming due to requireing some very small cutters using tiny stepover amounts.!! The tiny cutters also increase the chance of tool snappage to scarey levels. .:uncomfortableness:

The multi figure plate is the real challenge to cut and keep detail and will take a massive amount of time and again due to tool breakage potential not something I'd like to do for the laugh.?? . . Can you imagine being 18hours into 20hour job then the toolsnaps and wrecks the mould. . Arghhhhhh don't come near and the air would turn blue in London even thou I'm in yorkshire.!!

3D printing being a wide field ;-) If its very high detail would have though SLS or DMLS would offer the resolution possibly requiring intermediate steps to make a working mould, sure can get SLS baked to short run injection mould level.

Milling into wax or foam and then investment casting from there.

Spark erosion into hard steel for longer run moulds.

No way of getting round that it is a lot of hours on very expensive machines, once you have the moulds, small as they are ,raw material is going to be pence per shot.

Is this one of these artistic ambitions meeting the cold light of day moments though.

"If you only knew what it was for you'd bite my hand off at the chance to become a partner!"

Hay tomorrow, always tomorrow....

If its a sure fire winner, producing moulds goes from expensive to scary expensive , producing parts is cheap, someone will bite your hand off to put the money up to have the moulds die sunk, which would then give you a realistic budget to work from.

Musht, thanks for the info, I agree with everything you've said. Unfortunately the problem isn't the process, but the file format.

I've got a mould housing and IM company ready to go, the only thing I don't have are the inserts. There are loads of engraving companies from Hounslow to Hong Kong who can engrave the detail.....as long as they are in IGES/solid format. I've also found investment casting companies who are happy to do a quote, all I have to do is....send them an IGES file :-) Same goes for spark erosion, etc. You can convert mesh files (stl, obj, etc) to solid in a number of packages, but only if they are less than 20,000 faces. Unfortuntely mine are bigger than this limit and I can't find anything that will do it - would love to be told otherwise!
I'm intrigued by your suggestion to bake an sls. Is that something you can do with SLA as well? I'd need the resolution of SLA as SLS is too grainy for me.

As you say, there is the option of a multi stage approach involving SLA then casting them, but that may be out of my reach. I thought it would be worth exploring the possibility that someone with their own set up might be set up for stls, so here I am ;-)

Hey Jazz,
I completely respect what your saying about the risks involved and I wouldn't want to be responsible for you uttering profanities. In terms of snappage I've got 3 x 0.3mm ball nose cutters and 2 x 1mm end mills going spare which I bought when I thought I could do it myself. Let me know if you'd like any.

Hi S,

what do you consider reasonable cutting times? As I would have to do it in sections per piece. Unfortunately my spindle is only a Kress 1050 FME and it does not like running for over 10 hours at a time. Time wise I sent you in an e-mail and 30+ hrs of cutting can get rather hair raising if things even get a chance to go wrong. I know that I would turn the air blue in Glasgow if something like that happened and I live in Edinburgh. While the moulds look very doable they need so very specialized cutting ability. I am looking for the firm I mentioned in e-mail and hope to find them so you can get the file ported to IGES.

Michael

You might like to take a look at this program for converting STL to IGES http://www.okino.com/conv/conv.htm

Phill

Hi Mr Marino,
Thanks for taking the time to look at the numbers, that's a lot of hours! I'm happy to have a relatively large stepover - and accept the loss of finish - if it makes the machining time doable. Jonathan - who is also looking at the file - has very kindly offered to do a small test piece based on a 0.1mm stepover to see what it looks like. I can't wait to see it!
The French company sounds promising, do let me know if you find their details. In the meantime I'll have a look at the weekend at the program Phil suggests (thank you Phil!) and will post any news...

http://www.3dprint-uk.co.uk/ take stl files.

http://i.materialise.com/blog/entry/...el-3d-printing, will produce metal prints which should be suitable for your processing.

I think you can upload an stl file for an online quote.

I'm late to this and read the thread but may have missed the point. If so apologies!

The program I use suggested under 10 hours cutting time, but I tend to treat it's estimates with a pinch of salt. Most programs do not ask for an acceleration value when calculating the machining time, so either they ignore acceleration or use a typical value. For detailed 3D work like this the acceleration will make a huge difference to the feedrate, in addition to chances of the tool breaking.

I'll probably try various stepovers and see what it looks like. I'm not too bothered about the cutting time as it's not like I have to stand and watch it, but if it fits in a day that would be nice.

(2000th post, yikes!)

Happy 2000 Jonathan:beer:

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Originally Posted by Jonathan

I'll probably try various stepovers and see what it looks like. I'm not too bothered about the cutting time as it's not like I have to stand and watch it, but if it fits in a day that would be nice.

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It's the thought of tool breakage and starting over again that curdles my noodle so caution is the only way and this add's time.??
Think You'll be lucky to do even the small ones under 12hrs and do them enough justice to be worth while.!

Congratulations Jonathan!

I've had a fresh look at DMLS since a couple of people suggested it. Unfortunately a big drawback is the surface finish, which appears to be similar to 240 grit. That's fine for larger items where polishing is an option, but not so for detailed work.
Prices are still very high... an eye watering quote to do a 1inch sample has just confirmed that!

I love a challenge and machine time is not a concern - water cooled spindle has run for 4 days constant in the past. Send me a sample file and i'll get back to you asap. will pm my email address

Was the OP ever able to get the models cut? As I have been working with some cutting protocols that might take the time down and then there is also FormLabs who are bringing out a true 3D printer (stereolithography proper). It is in plastic, but the resolution is fine enough for what you are wanting to do.

Michael

Hi Michael,
Thanks for asking. Jonathan and I are making good progress with the machining. We've done some R and D tests cuts which have been very successful and are close to machining the moulds. Jonathan couldn't have been more helpful with his positive "let's give this a try" approach.
I'm waiting on some new cutters to arrive at the moment, but when we have some news I'll let you know how we get on.

Also, thanks for the printer info, I'll have a look at it.