we’ve now run a pretty significant number of Delrin mouthpieces on the CNC machines, so I think I’ve got a pretty good handle on what’s happening…..

(1) the mouthpieces play VERY well right off the machine

(2) the curves are astoundingly accurate, almost never require any adjustment at all

(3) the tables are pretty much dead flat

(4) the tip rails sometimes require a little touch up….we’re working on that. We suspect we can improve the programming issue.

(5) the threaded chamber has been a little problematic in that there’s been a little loose “flash” remaining around the threads that I sometimes have to clean up. 

(6) I personally play test every one, and simply do what I believe appropriate to make each one play its best

(7) we initially had an issue with very slight tooling marks visible on the exterior, but this is now resolved. This was strictly a cosmetic issue.

(8) The “memory” issue just doesn’t seem to be a problem.

(9) working with Delrin has been a little bit of a learning issue, but we are true believers in its acoustic qualities and will be introducing several more Delrin models this year. Making saxophone mouthpieces has been a new business to EMR Machine, so there has been a little bit of a learning curve there as well. We get better at this every day. They are highly skilled at what they do, and we just need to figure out the subtle nuances of the mouthpiece manufacturing business.
																																												
> On Apr 14, 2016, at 4:43 AM, barrylevine barrylevine@... [MouthpieceWork] <MouthpieceWork@yahoogroups.com> wrote:
> 
> [Attachment(s) <x-msg://46/#TopText> from barrylevine included below]
> 
> Very good question.
> 
> I'll be interested in Steve's response; but one possibility is the presence of "plastic memory" in the finished product due to stresses in long chain polymers comprising the mouthpiece material. The degree of accuracy you mention applies to metal items, but may not be attainable in machined thermplastic items
> 
> Considering thermoplastic items in general, that are molded out of shredded former items, small beads, or even powder, the smaller pieces retain a "memory" of their shape, resulting in internal stresses. Machining exposes such stresses , for example at a tip rail. The result could be slight warping. Play testing and touch up could be necessary, even in Delrin, which is claimed to have "excellent dimensional stability."
> 
> Barry Levine
> 
>  
> On 2016-04-13 11:01 pm, kevin@... <mailto:kevin@...> [MouthpieceWork] wrote:
> 
>>  
>>  
>> Regarding the advertisement on the Delrin MP-  the comments regarding the state of the art CNC machining capability and then a final comment that the facings are then all "hand finished" and play tested.  What I would like to comment and learn more regarding mouthpieces that are made with today's precision machining technology are-
>> 1)  With a MP that is properly held for cutting in a CNC machine, a good CNC machine today is capable of 0.0001" tool path precision (higher end machines are even better than that).  So once a face curve tool path program is determined, and it can be very precisely cut why would there be any hand sanding done to it which would very easily introduce imperfections to the true geometry of the cut?
>> I could see MP's produced in high volume whereby the processing tolerances are lax (to coincide with a market price point) having flaws that need correcting, but for a $500 to $800 higher end MP I would expect the MP to be an accurate reproduction with precise processing and tight tolerance expectations.
>> 2)  To be able to produce the tip rail and baffle accurately to the face curve would seem to be the more challenging aspect of this process of making a MP, hence the hand finishing would seem to have a roll in this regard.  But if the MP is machined with a 5-axis CNC machine whereby the dimensions of the body, tip rail, baffle, chamber are all able to be cut to the known coordinate reference of the part and program, then again if the MP can be rigidly held so that deflection is negligible for the precision of the cutting tool making it 's finishing cuts, then these features of the MP should be more accurately produced.
>>  
>> So perhaps my main question is- what is there about the technology that is falling short of achieving the expected result, and what are the imperfections left that have to be hand finished?
>> Or is there perhaps some defiency in the 3D programming, or cutting tool choice or capability?
>>  
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I hope this saves on the proprietor's hand and wrist wear and tear! Such machines ought to be able to reproduce any old mouthpiece design or new design, and do so at a very reasonable cost soon (assuming the volume is there to split set up costs.) 
Right now, my favorite trumpet mouthpiece is still made on a hand lathe, but that seems to be an oddity anymore. And I fear for what I will do if something happens to the Storks. The CNC off brand mouthpieces are high quality and often reasonably inexpensive. Once the tech process gets worked out for the more complex woodwind mouthpieces, it is the design and last little bit of QC and hand tweaking that will set the good apart from the great. There should be better intermediate mouthpieces for much less, soon.