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One for the techies again.

Without boring you with the detail, I'm getting involved the world of 3D printing in a musical consultation sense. Things like printing pla mouthpieces and other accessories. 

Very much in the early days at the moment but looking at the subtractive side as well as the additive (CNC machines)

Does anyone here have 3D printing and CNC experience?

  • Is there a significant difference between G-code for 3D and CNC?
  • Is there a difference in the file size, bandwidth used?
  • Quality comparison
  • Time taken on CNC compared to 3D

Ta.

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I have a small cnc machine, a Zenbot 1216. No experience with 3D though.

40 years ago, I could program a little with Assembler. G-code seems similar in that it speaks directly to the machine. Can't wrap my head around either of them now.

I use Vetric cnc software which makes it easier. Like using BASIC rather than Assembler.

Whichever route you go, I would advise using a stand alone pc with it. Mine has an old Dell with a minimal XP install and never goes online.

There is a bit of a cottage industry making bespoke designs in Vetric. Giving someone $50 for an hours work rather than spending lots and lots of hours trying to figure it out has its appeal. There's probably a similar service for 3D designs.

There are services where your design gets 3D printed. That might be cost effective if only a few parts are needed.

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15 hours ago, maynardgravy said:

Is there a significant difference between G-code for 3D and CNC?

  • Is there a difference in the file size, bandwidth used?
  • Quality comparison
  • Time taken on CNC compared to 3D

I can't imagine there is much difference between the type of g-code for printing and CNC: in the first case, the code moves the tool where you want material, and in the second case, the code moves the tool where you don't want material. The tolerances of a CNC machine must be higher than the 3D printer because it doesn't take the material to melting point, but the minumum feature size might be larger, too, because the size of the tool might mean it can't access certain places without a collision, or it can't make a very small internal radius.
Obviously, there are somethings you can do with additive manufacture that could not be done with a subtractive technology: blind cavities for example, and poyhedral infill, like the honeycomb in bones.

Edited by Nippy
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15 hours ago, maynardgravy said:

 

Does anyone here have 3D printing and CNC experience?

 

Some, of both.

15 hours ago, maynardgravy said:

 

  • Is there a significant difference between G-code for 3D and CNC?

At a fundamental level, no.  At a practical level, yes.

For a 3d printer the g-code (if it uses that approach) is always generated automatically.  You design and let the code generator do its thing.  You can't do better than it.  There's little you need to worry about in terms of technical details -- it is either automatic, or you use the standard setting for the material you're using.  Of course, if you want you can get directly involved (temperatures, speeds etc) but that tends to be the realm of the tinkerers.  The code is intrinsically based on multiple layers of the same thickness and the printhead moves around to deposit filament directly under it.

For CNC you can use auto generated g-code, but if you know what you're doing you can improve on it.  Even for the auto-generated stuff you'll need to know lots of stuff about the materials and cutters you're using -- speeds, rotation speed, depth of cut, etc, etc, each specific for the material you're cutting and the cutter you're using.  While you can work based on 'layers' that tends to be really inefficient and excruciatingly slow (and will wear the machine out), so you're better off working in terms of 'primitives' -- ie, 'put a cylinder x diameter y deep at that point'.  

And if you muck up with your settings a CNC will be capable of doing serious damage, so don't get it wrong...

There's also SLA based 3d printing, which isn't g-code based, but is based on 'resolution' (each layer is an image, not a set of instructions).  

16 hours ago, maynardgravy said:

 

  • Is there a difference in the file size, bandwidth used?

Is this ever an issue these days? 

But, to answer the question, well written cnc g-code is always teeny in size.  3d-printer g-code is always as big as it is (ie layers x detail per layer).  Badly written cnc g-code (or simply based on layers) is similar to 3d printer g-code.

SLA file sizes can get fairly biggish, but I can't see how that is a limiting factor.

16 hours ago, maynardgravy said:

 

  • Quality comparison

 

Properly written CNC g-code will give near flawless finish.  Layer based CNC can also look exceptionally good -- but to get that good finish will take forever.

FDM 3d-printing is always limited by layer settings, and you'll never get 'excellent'.

SLA 3d-printing is limited by layer settings, but finish can be truly excellent. 

16 hours ago, maynardgravy said:

 

  • Time taken on CNC compared to 3D

Well written CNC will be really fast.  3d prints are always slow.  Badly written CNC g-code is very very slow.

I suppose all the above is a waste of time -- if you want to do 'stuff' like that, then the question is 'can you do what you want with a SLA printer?'  If you can, then get one.  Proper CNC is very expensive and FDM 3D is only (IMO) good for prototyping.

As a final note, if I was doing anything involving mouthpieces etc I'd be thinking of SLA 3D printing moulds and delivering the product as polyurethane or silicone (depending on material properties required).

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16 hours ago, maynardgravy said:

One for the techies again.

Without boring you with the detail, I'm getting involved the world of 3D printing in a musical consultation sense. Things like printing pla mouthpieces and other accessories. 

Very much in the early days at the moment but looking at the subtractive side as well as the additive (CNC machines)

Does anyone here have 3D printing and CNC experience?

  • Is there a significant difference between G-code for 3D and CNC?
  • Is there a difference in the file size, bandwidth used?
  • Quality comparison
  • Time taken on CNC compared to 3D

Ta.

Custom designed mouthpieces is an interesting one. You’ve got to think that the tendency of brass players to use one of a small range of accepted “good” mouthpieces is more a limitation of technology than anything else. Mouths are so variable that a Bach 7C can’t possibly be the best mouthpiece for at least 50% of trumpet players (the ones I’ve known at any rate) for example.

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I've no idea about the terminology you've used but I once used Solidworks to design a prototype aerofoil. 

It was built by 3-D printer to a good standard except one part that delaminated (thankfully not critical to its performance). A piece of metal was inserted into it that was shaped using the same design but built on a CNC machine. The CNC "slipped" for whatever reason and left a notch near the trailing edge of the metal. 

I'm not sure that is relevant to the point you were asking but my experience of both manufacturing forms was marred as a result. 

The only thing I would say is to make sure that your design is realistic (I imagine it would be for mouth pieces) - e.g. neither method can make an interior hole without having an access point so it is impossible. 

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3 hours ago, The Generation Game said:

e.g. neither method can make an interior hole without having an access point so it is impossible. 

CNC can't.

FDM 3D printing most definitely can.

SLA 3D printing can, but you need to be a bit more careful with the design.

But your point:

3 hours ago, The Generation Game said:

The only thing I would say is to make sure that your design is realistic (I imagine it would be for mouth pieces) 

Is right.  All forms of 3D printing and CNC have 'complications' that make design that little more complex.  In general, you need to understand how the loads (etc) on the thing will work, and how the material properties of the 3D printed thing will work with the loads.

The biggie is with FDM 3D -- because of the laminated nature of the print, the print will have very different load properties in the x-y plane compared with the z-plane.

Note that this is the same as any other form of manufacture -- you have to know the properties of the materials and production process to design and produce the right end product.  But it does lead to complications -- eg, you can't produce a prototype as 3D FDM and just take that design and use to create an injection mould -- you'd need to redesign wall thicknesses etc.

[I like polyurethane for this reason -- you can actually take a 3d print, take a mould and use it to produce end-product in small volume (with careful selection of the polyurethane chemistry (but that's the great thing about polyurethane -- there's always a 'right' chemistry to choose from).  But that's the catch -- that approach becomes relatively very expensive beyond a few hundred items.  Great for low volumes though.]

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26 minutes ago, dgul said:

CNC can't.

FDM 3D printing most definitely can.

SLA 3D printing can, but you need to be a bit more careful with the design.

But your point:

Is right.  All forms of 3D printing and CNC have 'complications' that make design that little more complex.  In general, you need to understand how the loads (etc) on the thing will work, and how the material properties of the 3D printed thing will work with the loads.

The biggie is with FDM 3D -- because of the laminated nature of the print, the print will have very different load properties in the x-y plane compared with the z-plane.

Note that this is the same as any other form of manufacture -- you have to know the properties of the materials and production process to design and produce the right end product.  But it does lead to complications -- eg, you can't produce a prototype as 3D FDM and just take that design and use to create an injection mould -- you'd need to redesign wall thicknesses etc.

[I like polyurethane for this reason -- you can actually take a 3d print, take a mould and use it to produce end-product in small volume (with careful selection of the polyurethane chemistry (but that's the great thing about polyurethane -- there's always a 'right' chemistry to choose from).  But that's the catch -- that approach becomes relatively very expensive beyond a few hundred items.  Great for low volumes though.]

Cheers for the correction, @dgul. I was questioning myself when I made that statement. The 3D printer doesn't need to get "inside" the construction in the same invasive way that the CNC machine does. 

Edit to add: My prototype was built using SLA from Sonos NeXt for the reason that it needed high tensile strength and also high dielectric strength. 

Edited by The Generation Game
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11 hours ago, dgul said:

Well written CNC will be really fast.  3d prints are always slow.  Badly written CNC g-code is very very slow.

The speed is controlled by the G code which in turn controls the speed direction and distance of each axis independently ,speed is entirely dependant on what it`s set at via the code that is controlling it ,it`s the same for all CNC controlled machines  whether it be a mill lathe or 3d printer  ,some might have more axis's and they will all have different speed parameters /requirements  which will be dictated by many different factors from the power of the spindle motor to the type of cutter/print head used ,the material being cut or used for printing but feed rates are all set  by surface meters (mm)/foot (inch) per minute 

There are now plenty of integrated Cad/Cam  software that automatically creates basic G which is then adjusted to to suit Fussion 360 is very popular as it`s free for hobby use and it`s downloaded not cloud based 

 There are quite a few CAM  programmes that are designed for 3d printing with built in slicing software ,

As ever YouTube is your best friend @maynardgravy 

 

 

Edited by Long time lurking
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On 25/10/2020 at 07:46, maynardgravy said:

Is there a significant difference between G-code for 3D and CNC?

Basically no there is not , but speed and feed rates will be significantly different between the two but it`s all basically numbers controlling the speed ,direction and distance  each axis travels 

CNC =computer numerical control  

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On 25/10/2020 at 07:46, maynardgravy said:

One for the techies again.

Without boring you with the detail, I'm getting involved the world of 3D printing in a musical consultation sense. Things like printing pla mouthpieces and other accessories. 

Very much in the early days at the moment but looking at the subtractive side as well as the additive (CNC machines)

Does anyone here have 3D printing and CNC experience?

  • Is there a significant difference between G-code for 3D and CNC?
  • Is there a difference in the file size, bandwidth used?
  • Quality comparison
  • Time taken on CNC compared to 3D

Ta.

Experience with a bit of both.

No difference in GCode, each machine has specific setups and calibrations, but a part from that Gcode is interpreting distances, directs and speeds with which the tool - be it an extruder or cutting tip is passing through space. 

File size and bandwidth - cannot see any issue in regards those at at all for most practical uses.

CNC can be much higher quality finish and is generally faster. A CNC head crash is much more serious, you have to be really care with setting up and getting the stock you are milling / machining solid and in the right place in space, you need to do this for every run and every piece of material - expensive machines do this with clever positing sensing tools automatically.

CNC is severely limited in what shapes you can create, meaning you have to break down an overall shape into sub assemblies.

3D printing, can print more or less anything within the scope of the print volume. Mouth pieces are small and intricate, perfect for 3D printing, if every part is custom probably even more reason to go the additive route, once you have cracked the printing in pla / abs could always send to the design to increasing number of 3D print houses who are using sintering techniques to create metal and other parts - they have a huge range of materials they can print with with all sorts of properties.

Don't rule out uv resin printers,  for small parts like mouthpieces you will get more accurate prints than with the reprap style filament printer.

I would start with filament printer - don't think you even need one with two filament printer (for supports), have a play and the maybe look at resin, get used to the toolchains and find one you are comfortable with - Fusion, others for the 3D side, Openscad maybe - can be very good for parametric design. Once you know exactly what you want to produce then outsource CNC, it can get really expensive  and involved very quickly and is a massive time soak compared to additive to get right.

 

 

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1 hour ago, Long time lurking said:

Basically no there is not , but speed and feed rates will be significantly different between the two but it`s all basically numbers controlling the speed ,direction and distance  each axis travels 

CNC =computer numerical control  

There really is a massive speed difference.

I can take massive cuts in delrin (ie comparable to plastic in SLA, but actually much stronger).  If I want a simple vertical surface I might be able to do an entire block in a few passes.  I can plunge cut a hole through the entire block of material in seconds.  When doing CNC you can't really see what's happening -- it is just so fast, the chips fly everywhere and the mist occludes everything.  Anyway, with CNC often the main time bit is just clamping the bit in -- the machine flies and you get a part spewed out at the end.

Sure, if you're cutting some stupidly complex pattern then you'll end up in the same place, but really CNC isn't good at that (it is slow, but the real issue is that it'll end up wearing out the machine.

With 3D you're limited to doing a layer at a time, no matter what the surface is.

But the point is that with CNC you can work it out, perhaps simplify the design a bit*.  With 3D it doesn't make that much difference; it is all about the number of layers.

(*Eg, you might want to cut a logo into the part.  With CNC this might take as long again as the time for the main piece.  With 3D it probably won't have much impact on the total print time).

Anyway, it is all moot.  I've got £10k** of CNC spinning around, and a £300 SLA machine.  For for engineering bits in Al the CNC is king (faster and with strength in the final product), but for many jobs they'll be about as good as one anther, and the SLA can do detail much much more quickly with a capex that isn't noticeable.

[I'll also repeat the safety and training side.  Anyone can use a 3D printer.  My CNC weighs a ton and a badly programmed job could ruin the machine and a flying broken tool could do serious damage to anyone in the vicinity]

(** and that's a second hand machine)

Edited by dgul
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6 minutes ago, dgul said:

There really is a massive speed difference.

I can take massive cuts in delrin (ie comparable to plastic in SLA, but actually much stronger).  If I want a simple vertical surface I might be able to do an entire block in a few passes.  I can plunge cut a hole through the entire block of material in seconds.  When doing CNC you can't really see what's happening -- it is just so fast, the chips fly everywhere and the mist occludes everything.  Anyway, with CNC often the main time bit is just clamping the bit in -- the machine flies and you get a part spewed out at the end.

Sure, if you're cutting some stupidly complex pattern then you'll end up in the same place, but really CNC isn't good at that (it is slow, but the real issue is that it'll end up wearing out the machine.

With 3D you're limited to doing a layer at a time, no matter what the surface is.

But the point is that with CNC you can work it out, perhaps simplify the design a bit*.  With 3D it doesn't make that much difference; it is all about the number of layers.

(*Eg, you might want to cut a logo into the part.  With CNC this might take as long again as the time for the main piece.  With 3D it probably won't have much impact on the total print time).

Anyway, it is all moot.  I've got £10k** of CNC spinning around, and a £300 SLA machine.  For for engineering bits in Al the CNC is king (faster and with strength in the final product), but for many jobs they'll be about as good as one anther, and the SLA can do detail much much more quickly with a capex that isn't noticeable.

[I'll also repeat the safety and training side.  Anyone can use a 3D printer.  My CNC weighs a ton and a badly programmed job could ruin the machine and a flying broken tool could do serious damage to anyone in the vicinity]

(** and that's a second hand machine)

Good post.

I only CNC effectively 2D parts (probably more like 2.5D, if there is such a thing) out of sheet timber so a good deal of that doesn't apply to me.

A friend had had very good (to me) results with a very basic 3D printer and it's something I'd like to get into but I fear it would be a massive time sink. 

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On 25/10/2020 at 07:46, maynardgravy said:

One for the techies again.

Without boring you with the detail, I'm getting involved the world of 3D printing in a musical consultation sense. Things like printing pla mouthpieces and other accessories. 

Very much in the early days at the moment but looking at the subtractive side as well as the additive (CNC machines)

Does anyone here have 3D printing and CNC experience?

  • Is there a significant difference between G-code for 3D and CNC?
  • Is there a difference in the file size, bandwidth used?
  • Quality comparison
  • Time taken on CNC compared to 3D

Ta.

I learnt machinening on manual machines i have operated CNC machines many years ago and hated it 

At that point in time it was a whole different ball game CAD was very basic and every line of G code had to be manually inputted  this i really struggled with ,but on the whole back then it was the designers that done that

i eventually left that game but over the last few months due to the lack of work i started to look into it again it`s light years different to when i was involved especially the CAD/CAM  side of things 

I found this place brilliant it`s free and it caters for the complete novice and up ,it even has a section for kids it`s mainly machine based but it will teach you a basic understanding of CNC ,G code CAD/CAM 

https://academy.titansofcnc.com/

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46 minutes ago, maynardgravy said:

I', guessing this machine might set me back more than a tenner?

 

 CNC lathes are not that expensive in the scheme of things but you would still be looking at £5-10k half tidy second hand  one

The part in the video would be relatively simple to make  and very cheap 

I suspect they have a huge mark up ,i `m guessing most of the value is in the brand name 

I think if i was in your shoes with what knowledge you have of engineering /manufacturing i would be looking at outsourcing the machining to start with and see how it went from there ,take a cad drawing to a production shop and get a price per unit

Edited by Long time lurking
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15 minutes ago, Long time lurking said:

 CNC lathes are not that expensive in the scheme of things but you would still be looking at £5-10k half tidy second hand  one

The part in the video would be relatively simple to make  and very cheap 

I suspect they have a huge mark up ,i `m guessing most of the value is in the brand name 

I think if i was in your shoes with what knowledge you have of engineering /manufacturing i would be looking at outsourcing the machining to start with and see how it went from there ,take a cad drawing to a production shop and get a price per unit

Cheers for the info. I play on Bach mouthpieces (though I have at least twenty others). They can be picked up new for ~ £45 which I reckon is pretty good for the quality and precision. Tried some equivalent size Chinese tat and I don't know if it's the metal used but it's always been a duff experience, Some mouthpieces (like Monet) will set some idiots back 200+ quid...  fools and their money.

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5 minutes ago, maynardgravy said:

icked up new for ~ £45 which I reckon is pretty good for the quality and precision.

Materials would be less than a £1 or 2

From that video i would say machine time could be done in less than 5 minutes on a modern machine with auto bar feed ,the only trouble is you would not be getting much change out of £25k for such a machine even secondhanded 

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