From: none@none.com99   
      
   On 12/1/2025 12:58 PM, Bob La Londe wrote:   
   > I think I've been a victim of a constant pummeling of promotion,   
   > ignorant people asking if I 3D print, an onslaught of influencers, and   
   > being weak willed due to an oncoming sniffle.   
   >   
   > I ordered a 3D printer over the weekend.  Now here is the deal.  I can't   
   > think of a single think I "need" to print.  Well, there are a couple   
   > things that I could print FOR the new printer when it arrives, but if I   
   > never ordered it I wouldn't "need" to print those things.   
   >   
   > I've done the math.  For 99.99% of the things I make its cheaper and   
   > faster (time is money) to machine it from raw stock.   
   >   
   > 3D printing is slow.  Its not as good.  It still requires a CAD model to   
   > start. There is one place where it may be a trade off.  Using a slicer   
   > on a 3D model is semi automated, and it might be faster than doing CAM   
   > for a 3 or 3+1 milling operation for some jobs... I think.   
   >   
   > There is one area where it might have an edge.  Material price.  Hold   
   > on.  Hold on.  I know PLA starts at around $6 per pound on average and   
   > wrought aluminum at about $2-3, but the volumetric difference is huge,   
   > and with good 3D prints there is much less waste & much greater volume   
   > per weight depending on your machining strategy.   
   >   
   > After I get things figured out I'll probably be using much more   
   > expensive filaments.  ASA and carbon fiber reinforced  polymers among   
   > them.  Maybe even some of the metalized filaments.   
   >   
   > I have some logistical problems.   
   >   
   > 1.  I don't really know squat about the basic nuts and bolts of 3D   
   > printing (filament printing).   
   > 2.  I don't have a good clean room (not lab clean room) I want to use   
   > for printing.   
   > 3.  I don't know what I want to print.   
   >   
   > I thought about mimicking some of the work by Print Shoot Repeat, but I   
   > have already machined receivers from metal.  I'm not sure what would be   
   > gained by making a weaker if lighter receiver, and of course it only   
   > works for certain types of receivers where the force is mostly managed   
   > and contained within the upper like a Glock, AR, SR40, etc.   
   >   
   > I did have a customer once tell me to go pound sand once, because I   
   > wouldn't add 3D test prints and multiple iterations to making his parts   
   > for the same price as making his parts.  "Price sounds great.  Now do   
   > all this extra work too and you got a deal."  Honestly I don't want that   
   > customer anyway.  I don't mind doing more work, but I expect to get paid   
   > for it.   
   >   
   > Some of you guys must have gotten dragged kicking and screaming into the   
   > 3D print world.  Tell me what its better for than subtractive machining   
   > other than a handful of parts that can't easily be machine.   
   >   
   > I do see where injection molding is good for production parts, but   
   > injection molding makes a stronger part in seconds per cycle.  3D   
   > printing escapes me and yet I have fallen victim after a long time   
   > struggling with finding significant advantages.   
   >   
      
   I've recently run into two things that may expand the scope of 3D   
   printing in my mind.  No real epiphany here, but maybe an expansion of   
   scope.   
      
   One I already knew and mentioned.  Undercuts.  You can 3D print stuff   
   with undercuts impractical or evne impossible to make by sutractive   
   machining without complex setups, and changing relatively simple single   
   structures into complex multiple part assembled structures.  I'm talking   
   about things beyond a non-uniform parting line.  I had a customer   
   recently send me a nice 3D .stp STEP file.  One of the few that didn't   
   translate broke or with artifacts.  They had 3D printed a mold from it.   
   There are many things wrong with plastic for mold making, but was   
   injecting a soft cure media, and the undercuts did not prevent the part   
   from being demolded.  A machined aluminum mold would be superior for   
   this media for many many reasons, but cutting it would be a lot of work   
   requiring very very small cutters.  I don't think I could tilt the plate   
   enough to use those tiny cutters with their very short stick out enough   
   to cut the features with crashing the tool holder into the part.  I   
   suggested some alternatives, but I have not heard back from them.  That   
   last part is no surprise.  When I tell people the truth about what they   
   want they often ghost me.  I prefer that to those who imply I am a liar   
   or competent, and they will just get somebody who knows what they are   
   doing.  In their case I don't think I would make their part by   
   subtractive machining even on an articulating head 5+ axis machine.   
   Maybe...   
      
   Parts where the raw material cost is.  You need a bronze bushing.   
   Bronze is expensive.  You can usually buy a bronze bushing cheaper than   
   the raw stock to machine one.  If you are setup for it, and have been   
   saving scrap you might be able to cast a bronze blank and then finish to   
   spec, but generally the raw material is expensive.  If a usable bushing   
   is already available its probably cheaper.  How about 3D printed bronze?   
     You might make the argument that, "Sure, that's great if you can stock   
   10 grand worth of bronze powder,and you already have a quarter million   
   dollar laser sintering 3D printer.  The part is cheap, but the barrier   
   to entry is quite high.  No.  There are filaments that can be printed   
   (according to the manufacturer) on the same printers as PLA as easily as   
   PLA.  I can only assume they mean with a hardened steel or carbide   
   nozzle.  At this point I am falling back on sales propaganda, but it   
   might have some potential.   The thing is its not the price of PLA.  A   
   1/2 kg spool of aluminum filament is over two hundred bucks.  Amazingly   
   a 1/2 KG spool of bronze filament is a little less (not much).  Still   
   its expensive, and to finish with a full metal part you have cook it in   
   a furnace after printing to burn off the binder.  It sounds like a   
   compromise part, but maybe there is something there.  I'm leaning   
   towards probably not.  If I already have a furnace (I do) I think it   
   would still be faster and cheaper to cast a blank and machine to spec.   
   There may be something there, but I am sure the nuance escapes me.   
      
   Well, I have a dozen(+) blanks to cut from wrought stock and a bunch of   
   molds to cut.  Another Sunday spent in  the shop trying to catch up.   
   Hopefully nobody falls, dies, or has a personal emergency today dragging   
   me out of the shop yet again.   
      
      
   --   
   Bob La Londe   
   CNC Molds N Stuff   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)