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  1. #11
    Super Moderator curious aardvark's Avatar
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    Jul 2014
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    8,310
    Pretty much all the car stuff, totally lost on me :-)
    I literally only used a car analogy because this morning we drove past a ferrari on the road (going 'garumberrhum') and a ferrari dealership a few minutes later. And it's rare so it was in my mind.

    The big machines sound like stratasys setups.
    They are expensive - I mean really expensive. But while they don't live up to their price point - they are good.

    They also use locked in propriatary filament cartridges.

    I've never seen one in bits - but they do have a good reputation for reliability.

    As for speed - I've seen machines printing at 300mm/s with a 600mm/s travel speed.
    A few years back it was 'the thing' you did' if you were a manufacturer.

    Then creality appeared and started making silly money and everybody went: speed ? what's your hurry buddy ? buy this cheap printer instead and slow down and chill out.
    And they splashed so much money around youtube, that everybody just forgot how printers should be made and what they were really capable of.

    So far I have found on all my machines that the speed limits are purely mechanical. That's with decent pla.
    many filament types really won't print that fast. I tend to max out flexible tpu at 30mm/s. That gives me clean retractions, tricky on a flexible filament.

    But with pla - it'll print as fast as the machine can move.

    I have a very cheap delta with absolutely no frills. At 205c it'll happily pump pla out at 130mm/s and 0.3mm layer for pretty sharp and clean prints,
    I mean if you want really dirty - at 215c it'll got up to 150mm/s at 0.4 layer height and uses a 0.5mm nozzle.
    The quality is utter shite - but it's the mechanics of the printer that are the main issue - not how fast I can pump out pla.
    There is a real limit on how fast you can poush filament down a bowden tube.
    It's one reason direct drive is always preferable to bowden.

    I could probably beef the cooling up and print at a higher temp, but I can't be bothered.
    And there are a bunch of other reasons she won;t go any faster.

    With the sapphire - my current speed limits are simplify3d. I simply can;t get it to go past 200mm/s.
    I'm pretty sure the printer will hit the advertised 300mm/s actual print speed.
    But simplify3d just refuses to go that high.

    But yeah recidivist print speeds are definitely something I CAN lay squarely at crealitys feet.

  2. #12
    Thanks--all good stuff. I bought the Creality on my own nickel as a trial basically-and at $350 bucks it has already paid for itself in making optical bench parts that can cost $1000 of more, But I am sure it is over-advertised and maybe a bit obsolete. As I mentioned that parts are all "generic" so it can be maintained forever--sort of like a model A ford. (;->
    . But if we decide that 3D has use in the lab (and it does) we will probably opt for a better machine when the time comes. Your Sapphire shines here. And now that I have an inkling about what I am doing, I can pay more attention to the items that you mention.

    Software is another issue--I work 2 contracts right now and am split between Solidworks, Inventor and Fusion. I only know option 3 and have ME"s do the designs on the other 2. Software breeding is a real problem in the engineering field-I have the same problem with electrical design. Someone landed an Altium circuit on my desk the other day and at $7000/seat I told them to redraft it. Besides I haven't used it in 10 years.
    I never can be sure what software methods are really best--I think a lot of skill goes into that and I admire that vendors like Fusion even write it. I cobbled a crude python script to break out the Gcode, and comparing fusion to Cura for example reveals a lot of differences. Both make sense of course --so which is best! I certainly am not the guy to know. Simplfy3d is priced right and I would guess it is tuned pretty well since that is their main focus. All fun stuff of course-this took a whole new life since 50 years ago!

    Thanks
    Fritz

  3. #13
    Technologist
    Join Date
    Aug 2020
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    United Kingdom
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    155
    hi Fritz I thought there might be a music connection there some where - wasn.t sure about the name of the cleft you use as a logo I am a rather poor piano player as an English comedian remarked " all the right notes but not necessarily in the right order") and our music tends to have only the treble and Base cleft.It sounds like we have had very similar careers but on opposite sides of the Atlantic, but I did spend some time doing research in Boston and living in Concord MA.On the question of Aspherical mirrors a few years ago we did quite a bit of work on metalizing mirrors for automotive prototypes which had been produced by 3d printing. The main problem we encountered was build lines including slight layer shifts and surface texture. To cut a long story short we found that sanding and painting then sanding some more was very laborious. In the end with the aid of a polyester resin manufacturer we developed a special spray coating with a very small "shrink back" and ease of sanding. Though the quality of 3D printing has greatly improved we still use this process.Taking a automobile head lamp as an example the process consists of using conventional spray painting techniques to "bury" the surface texture the applying, again spray painting, an extremely thin film of an epoxy resin on the surface of the mirror.Once the epoxy is fully cured using a water based process similar to the traditional way of silvering say bathroom mirrors we deposit a reflective silver film which we then passivate with Tin to reduce tarnishing.

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