G3 Forum

In the Workshop : Constructors' Questions and Answers => Best Tool for the Job? => Topic started by: John Candy on January 12, 2018, 08:48:28 AM

Title: 3D Scanning and Printing.
Post by: John Candy on January 12, 2018, 08:48:28 AM
3D Scanning and Printing.

I am on the verge of taking the leap into 3D, with a view to producing my own scale figures ("British" folk in 1930s/40s/50s garb)since available items are either wrong scale or modern American/Continental fashions (women in Jeans, blokes in Stetsons, shorts or Lederhosen, etc.).

Also want to be able to produce patterns for casting loco and rolling stock parts (particularly carriage sides) as well as architectural subjects, to produce more authentic buildings.

I know that the finer the printer output, the better the finish and am looking at hardware in the 20 to 100 Micron range. The two technologies available are SLA (Stereo Lithography which uses liquid resin) and FDM (uses reels of plastic thread).

There are few affordable (for hobby use) printers which can print below 100 microns, one being the Cel-Robox-2 (FDM type) and the other FormLabs 2 (SLA and much more expensive and potentially "messy" but is said to give better results).

Since CAD is not my forte, I shall be relying in part upon being able to scan subjects and manipulate the scans to produce the correct scale output.

The first step will be to acquire the scanner and see whether I am competent to produce the necessary files (and that the scanner can capture sufficient detail to produce decent models).
The scanner I have been looking at is the Sense 3D , a handheld scanner which gives more flexibility than a fixed camera type.

I know some of you have experience of 3D (either as a producer or a customer of a scanning service) and hope you can provide feedback on experiences with this technology.

Regards,
John.
Title: Re: 3D Scanning and Printing.
Post by: Spitfire2865 on January 12, 2018, 01:18:37 PM
If you need help designing some components, I can give you a hand. Im good at artificial 3D design such as rolling stocm parts, but am absolutely hopeless at anything natural or organic.
Title: Re: 3D Scanning and Printing.
Post by: Gavin_B on January 12, 2018, 06:57:29 PM
I have 2 Wanhao I3+ FDM printers,  they can print a layer height of 40 microns.   Well setup they are good printers.  Also look at the Wanhao D7 resin printer which is similar but cheaper to the form2.

Title: Re: 3D Scanning and Printing.
Post by: LankyTank on January 12, 2018, 07:07:57 PM
John,

If you haven’t done so, it might be worth talking to Alan at Modelu. Could save you a bob or two. These are the outfit that scan you at model Railway shows, suitably posed, then produce ‘mini me’s’
Title: Re: 3D Scanning and Printing.
Post by: John Candy on January 12, 2018, 11:36:11 PM
Thanks for the feedback, particularly Trevor for the kind offer of help with the CAD aspects.

 I have followed up Gavin's suggestion of the Wanhao brand which I had not previously looked at.

I particularly want an enclosed cabinet type (one reason for the Robox being high on the list, the other being the 20 Micron capability) and there is a new Wanhao enclosed model "Duplicator 6" which can also print down to 20 Microns but at not much more than half the price of the Robox, so it is now high on my list , see https://www.3djake.uk/wanhao-3d-printer-spare-parts/duplicator-6-with-cover#js-faq (https://www.3djake.uk/wanhao-3d-printer-spare-parts/duplicator-6-with-cover#js-faq)

Still mulling over scanning options.... have just become aware of "Photogrammetry", where software generates 3D images from a series of ordinary digital photos taken with camera or smartphone. Seems to involve a subscription with processing done "online" with uploading/downloading files from a remote server.

Regards,
John
Title: Re: 3D Scanning and Printing.
Post by: cabbage on January 13, 2018, 02:08:42 PM
John,
You are in the grip of an obsession!!! 20 MICRONS!?!?!? that equates to 0.02mm x 22.6 = 0.452mm in real world. I am printing on my machine at 0.2mm layer and to be honest I cannot tell the difference between that and 0.06mm other than the vast increase in time taken for the latter layer depth.

If you are going to print people at 20 Microns then there will be  3,982 layers for it to print a (scale) 1.8m high person....

Draw a circle 2mm in diameter with a 1 mm centre.
Move back until you can no longer see the circle, i.e. it goes solid.
This is the limit of the resolution of your eye. (Having Glaucoma this test is done every 3 months!)

Divide the distance by four and this is how close you would have to be to notice a distance of 0.5mm. Standard machine stitching is 2.1mm or four layers to every stitch on the shirt...

regards

ralph
Title: Re: 3D Scanning and Printing.
Post by: Doddy on January 13, 2018, 03:38:45 PM
Keep going John, you are on the right track!

I have recently had my eye on the results of my friends industrial grade 3D machine with the following specification:
However, I wont be going with that machine as having had G3 scale Class 45 cabs printed at 16 microns per layer, I know well what the difference is, so for your stated purposes of producing masters for casting I know what I would aim for myself. I will qualify this in that I had the printing done commercially using layers of curable liquid photopolymer onto a build tray creating exceptional detail, surface smoothness and precision.
Secondly, - Scanning
Your proposed scanner only has a 1mm resolution. Since the quality of the 3D print depends on the quality of the scan, I would suggest this model is not going to deliver much, particularly as  talking to Alan at Modelu, he confirmed that the software has been optimised for scanning people and that items such as whistles and other locomotive fittings have caused him many problems scanning and printing, particularly as the memory of the unit is very, very small and cannot accommodate fine resolution scans of large items.

Talking to Alan about scanning class 40 and 45 bogie parts like buffers and axleboxes it became quite apparent that Alan thought it was thoroughly impractical.
There is a very good handheld unit which is independently powered (batteries) and has the finesse of very large memory capacity and a scanning resolution down to 0.00x microns- but you will need £20,000 for that baby!
Title: Re: 3D Scanning and Printing.
Post by: John Candy on January 13, 2018, 05:48:21 PM
Ralph,
A few years ago I was discussing with Mike Williams a proposal to buy a 3D printer and at that time the resolution of affordable types was more than 100 microns (which to me sounded very fine) but Mike said it would not be good enough for producing patterns, so I gave up on the idea. If I were printing scale figures (people) then I would not go down to 20 microns....50 to 100 would probably be good enough given the undulating surfaces. However, if I were making patterns for carriage sides (or the cab for LMS 10000.....that is still on my project list) then I would not be happy with striations which would have to be sanded down.
The limited printing footprint (approx. 8" square) means that long, flattish, patterns would need to be printed in sections.

Doddy,
Yes, I saw the hand held scanner which was advertised at "less than $20000" ....... it's not on my shopping list!

Thanks for the input from Modelu, I had in mind to use the 3D Sense (or similar cheapish handheld) just for scanning people and large objects which would be reduced substantially in size for printing and where minor striation would not matter too much (e.g. architectural subjects with textured surfaces). I have just taken delivery of a new HP laptop with the i5 8250 quad core cpu (latest Intel 8th generation chip) which I was assured can cope with 3D scanning and (via USB 3.0 connection to scanner) should overcome memory/storage difficulties.

For high resolution work (carriage sides, etc.) I am now veering towards photogrammetry and 3D CAD.

Regards,
John.
Title: Re: 3D Scanning and Printing.
Post by: Andy Mould on February 22, 2018, 11:38:47 AM
Have a look at the 3D forum section of RMweb and Simon Br Blue posts he has purchased a formlabs form2 which is kind of on my list although expensive and he has now started his own prints I am watching with interest the progress we also have G1 member in our local group with a form 1+ he has produced some good work with it but it not all plain sailing especially as I’m looking to print ‘waxes’ to go straight to lost wax casting.
Title: Re: 3D Scanning and Printing.
Post by: cabbage on February 22, 2018, 12:47:20 PM
You can do "Lost Wax" using PLA. We have made parts using Aluminium in a Plaster of Paris mould for my Nieces "Huffacker" inlet manifold for her Landrover.

regards

ralph
Title: Re: 3D Scanning and Printing.
Post by: Doddy on February 22, 2018, 01:24:29 PM
You can do "Lost Wax" using PLA

Unfortunately PLA won't burn away in a hot kiln in the same way wax does.
Title: Re: 3D Scanning and Printing.
Post by: cabbage on February 22, 2018, 05:27:35 PM
We used an oven! The PLA melted out of the plaster cast and puddled in the tray underneath. The aluminium was melted and then poured into the voided cast.

Regards

Ralph
Title: Re: 3D Scanning and Printing.
Post by: Doddy on February 22, 2018, 06:12:14 PM
We used an oven! The PLA melted out of the plaster cast and puddled in the tray underneath. The aluminium was melted and then poured into the voided cast.

Regards

Ralph

GOT IT!


(http://thumb.ibb.co/ie6ATH/5166714809_aea1a4a93e_b.jpg) (http://ibb.co/ie6ATH)

cdn images (http://imgbb.com/)
Title: Re: 3D Scanning and Printing.
Post by: Andy Mould on February 22, 2018, 09:43:52 PM
One reason to go for SLA as you can print in ash free casting resin that can go direct to lost way, hence its the favoured system of dentists and Jewellers
Title: Re: 3D Scanning and Printing.
Post by: Doddy on February 23, 2018, 06:49:25 AM
One reason to go for SLA as you can print in ash free casting resin that can go direct to lost way, hence its the favoured system of dentists and Jewellers

(http://thumb.ibb.co/ebLzNc/happy.jpg) (http://ibb.co/ebLzNc)

That's what I thought as well, the master wax image SLA would need to burn off within complicated moulds where as the PLA would just pool in pockets and ruin the casting.

Title: Re: 3D Scanning and Printing.
Post by: MikeWilliams on February 23, 2018, 08:36:42 AM
Could somebody post a picture showing the surface detail from one of these affordable machines please? I know expensive machines can be reasonable but pi tures and samples I have seen from home printers are mainly dreadful except for flat pieces like Ralph's building where they can be good. A closeup of a curved surface maybe?

Mike
Title: Re: 3D Scanning and Printing.
Post by: wolfstone on February 23, 2018, 10:39:12 AM
I have had a tail lamp printed from an actual lamp that I measured and drew in AutoCAD Fusion 360. In the first print the handle was too delicate. Following a re-draw I hope to have some at the AGM if anyone is interested.

Tim
Title: Re: 3D Scanning and Printing.
Post by: wolfstone on February 23, 2018, 10:46:57 AM
Further to post here is a
(http://thumb.ibb.co/mveAfx/tail_lamp_3d_print.jpg) (http://ibb.co/mveAfx)
photo
Title: Re: 3D Scanning and Printing.
Post by: Doddy on February 23, 2018, 11:50:25 AM
Could somebody post a picture showing the surface detail from one of these affordable machines please? I know expensive machines can be reasonable but pictures and samples I have seen from home printers are mainly dreadful except for flat pieces like Ralph's building where they can be good. A close-up of a curved surface maybe?

Mike

It is a case of the relationship between the models scale and the dynamics (size) of the nozzle used, the print layers and a whole host of other factors.

As can be seen from this Aston Martin DB4, curves are not a problem on cheap 3D home printers . . .

(http://thumb.ibb.co/k1Zkxc/71582062_astonmartin3.jpg) (http://ibb.co/k1Zkxc)


This webpage shows the difference between 50micron and 16micron printing for an N gauge model locomotive.... https://www.shapeways.com/forum/t/black-high-definition-acrylate.39425/

And again for N gauge Networker EMUs http://www.rmweb.co.uk/community/index.php?/topic/99539-networker-emus-in-n-gauge/page-2

This is a 20micron prop spinner.

(http://thumb.ibb.co/eQHxcc/IMG_1285.jpg) (http://ibb.co/eQHxcc)


This G3 Scale Peak cab is printed on a commercial Polyjet system at 16microns and still requires a good cleanup, and whilst paint can be used to fill the lines and layers, rubbing the detail off grills and louvres and such, has put me off damaging the cab so far.

(http://thumb.ibb.co/cmo0Vx/2015_11_14_08_19_03.jpg) (http://ibb.co/cmo0Vx)

This G scale Hungarian V42 took 60 hours of printing and 70 hours rubbing down with sandpaper to get a smooth surface... http://www.instructables.com/id/V42-Electric-Locomotive-in-G-Scale-for-Garden-Rail/

This 'Big Boy' was printed over 1000 hours http://3dinsider.com/print-your-own-scale-model-4-8-8-4-big-boy-locomotive/

One of the keys to a good surface finish is the size of the filament used....

(http://thumb.ibb.co/dSFdiH/original_prusa_i3_mk2_kit_4.jpg) (http://ibb.co/dSFdiH)


And the post processing of the printed items, be it with the use of generous amounts of sandpaper or as can be seen below - by the use of Acetone vapour baths.

(http://thumb.ibb.co/bOLpqx/Acetone_Vapor.jpg) (http://ibb.co/bOLpqx)
Title: Re: 3D Scanning and Printing.
Post by: MikeWilliams on February 23, 2018, 12:07:34 PM
Thanks Doddy,

"16microns and still requires a good cleanup, and whilst paint can be used to fill the lines and layers, rubbing the detail off grills and louvres and such, has put me off damaging the cab so far." just about sums up my experience too, so printing direct to wax leaves no opportunity to clean up except on the final cast brass part.  I think the process is great for some things but is not yet the utopia that some firms are claiming for their cheap machines.  And, to put into perspective, what would that Peak cab (which is just fabulous!) cost to print commercially?

The Aston Martin is no real help with models because even 0.5mm layers wouldn't show on that and the originals were filled and rubbed down many times anyway.

Give it a few years and I suspect it will be the only way to make small components.

Mike
Title: Re: 3D Scanning and Printing.
Post by: Doddy on February 23, 2018, 12:29:38 PM
I was being flippant about the Aston Martin for precisely the reasons you point out.  ;D

The single (not pair) printed Peak Cab would be equal to three of your wagons at list price.

On all the variety test printing I had done in 2017 on Rep-Rap and PolyJet style machines to make an evaluation on print quality, there was an enormous amount of finishing to do.

As can be seen from my previous post Re: the V42, the builder printed that on a home printer but still spent 70 hours sanding it down. So your observations on post finishing are correct.
Title: Re: 3D Scanning and Printing.
Post by: cabbage on February 23, 2018, 08:08:51 PM
Here is a milk churn. This is printed at 0.2mm layer height, 0.4mm nozzle, PLA, 10% infil, and 200% frame rate.I took about 20mins.



(http://thumb.ibb.co/mdAqDH/WP_20171224_12_16_13_Pro.jpg) (http://ibb.co/mdAqDH)


Regards

Ralph
Title: Re: 3D Scanning and Printing.
Post by: Doddy on February 24, 2018, 03:10:29 AM
This is printed at 0.2mm layer height.

200Microns no less! This kind of supports the discussion on clean-up issues.
Title: Re: 3D Scanning and Printing.
Post by: Andy Mould on February 24, 2018, 08:48:45 AM
My wife is a Jeweller and when she designed her engagement ring it was printed straight to “wax” and I was most impressed by the quality of finish that was almost polished.

One thing that is clear is that 3D printing is moving forwards almost by the day for quality and cost.
Title: Re: 3D Scanning and Printing.
Post by: cabbage on February 24, 2018, 10:07:08 AM
Well.... This is also printed at 0.2mm layer. I could go to a higher resolution but since I am going to prime and paint it I really don't see any reason to.


(http://thumb.ibb.co/iTbhdH/WP_20180224_10_02_20_Pro.jpg) (http://ibb.co/iTbhdH)


Regards

Ralph