Post by suctionhose on Jan 10, 2017 12:41:08 GMT
Over Christmas, it isn’t prudent to bash rivets, machine metal or be otherwise productive in any way, so I “made” my first 3D Model.
By means to better understand and appreciate what 3D modellers are doing and why, I downloaded Fusion 360 and produced a model of a prominent feature required for the 1880’s Fowler Ploughing Engines my friend and I are building in 3” Scale.
Here is my story:
The item is about 235mm long, hollow in the back and having a section through the arch about 15mm x 28mm. Previously, being a “Traditionalist” I would have manually cut the letters out of 16g brass and silver soldered them to the main body, which would have been band sawed and milled to shape. Nowadays, I might have had the letters laser cut instead or possibly forked out to have them engraved (with background machined way leaving letters proud which is time consuming and expensive)
Either way, there's a couple of days work involved. As I need two off this time (for two engines) there was reason enough to dabble in 3D and see if a pair of nice sand castings would result.
Firstly, acknowledging that I had to learn how, the Model took A LOT OF TIME. I found I had to sort out the shape in 2D Cad first because “sketching” in 3D is quite difficult and slow to work with. The process went something like this: Scale photographs – 2D shape - check on engine – modify until happy – lay out text – adjust dimensions and text positions numerous times and finally use the 2D dimensions for “sketches” in Fusion 360 to generate the Model (which took a long time too especially putting draft on all the letters).
The various sketches were extruded into bodies – you really need to plan what to sketch and which plane to work on…. I had a 4 different attempts to establish “a workable methodology” - you probably get used to it with practice – the text went backwards because of the plane I chose – redo it again – adding draft to text is tedious and time consuming (Maybe I was doing it incorrectly but WOW, there’s A LOT of help forums about “Trouble with Font in 3D”!
Anyway, after DAYS of staring at the screen not blinking, Version 34 of this simple part emerged and was declared “ready for production”.
At this point I began to think more deeply about the likely steps from Model to Metal. Naively, my concept was “3D print a PLA pattern” for a sand casting (first preference) or a wax for investment casting (because a web search will quickly locate a “Prototyping Company where one off’s from your STL file are entirely normal”! (Is that sufficiently dripping with sarcasm? Perhaps not…)
Seems the 3D Print / Investment Cast industry is really aimed at the jewellery industry where they’re trying to rob the Jeweller of his or her craft and render them “a designer” rather than perpetuate the craft they supposedly practice … Anyway, being a designer is soo much nicer than getting all dirty with that yukky wax and stuff... (Was there enough sarcasm that time?)
So rejection from that quarter on all sides both here and abroad based on size alone. One last shot was a Company 1000kms distant that “Specialised in One offs and Prototypes”. (Here’s me thinking, how can make any money doing that?)
Well actually, they only do “One offs and Prototypes” if you want to proof your production run before giving them an order for 1000’s more which by the way you are going to remunerate them for the One Off cost a hundred times over – Well yeah, I can see how you could make some money doing that!!!)
I used to wander into a foundry with a bit of wood and get a one off done for a few dollars in the hand. Heck, we used cast gunmetal at home practically for free!
Traditional methods have been systematically eradicated “to cut costs” and replaced by technology that is a “free download”. But it requires the services of a Company having a significant investment in fancy equipment. How can that “cut costs?” It’s just accountants playing games….
The 3D technology is fantastic. It will empower fertile minds to “create” without limitations of geometry or available processes. More variety than ever in design is possible, ‘nicer’ aesthetics, without those boring old engineers “dragging creative talent down with their realities”.
This experience though, clearly demonstrates to me that traditional skills; foundries, machine shops and most other forms of manufacturing are sadly missed. The new technology is not a substitute. It compliments certainly. It expands the range of possibility.
Of course, the 'new' will dominate because it’s NEW. Clean too. And trendy and easy to get creative by clicking your phone. Using 3D with a specific outcome in mind is a skill in its own right – no doubt about that - and the work by people on this site is tremendous as is the ability to see it from anywhere on Earth!
But I dunno… I might knock up a simple pantograph and use the $80 Dremel….