Monthly Archives: May 2018

3D Print Orientation and What To Do When It’s Wrong

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As promised in last week’s post this week I’m going to share with you how to identify if your 3D printed model has been printed correctly.

So what do I mean by correctly printed? Back in October of 2017, in a post which you can find here, I shared with you the new feature from Shapeways which allows the orientation of the print to be set.  This means parts such as a locomotive shell can be printed with the roof on top ensuring the smoothest detail, rather than upside down like a bath tub.

However sometimes, even though the print orientation has been set, some models slip through the printer’s checks and get printed in a cost-saving way; this normally means upside-down.  But how can you tell?  Well, there are a few tell-tale signs which are caused by the print process which give away the orientation of the print.  These signs can be seen when the model is first delivered but given the transparent nature of the material it is fairly hard to spot and nearly impossible to photograph.

So the first thing I always do with any model is soak them in Goo Gone for 24 hours, which makes them opaque, rinse them under warm water and leave to dry for another 24 hours.  Below you can see a set of Alco C-855 shells which have been through this process.  These shells were ordered with the print orientation set so they printed the right way up and at first glance they look good.

But a closer inspection reveals they have been printed upside-down.

The first clue is the direction of the print shadow. The print shadow is the area under a section which sticks out.  In order to print this section support material is required to literally support it. However, where this support material comes into contact with the actual model it leaves a slighty rougher finish which is called the print shadow.  For example, in the image below you can see the print shadow running up from the bolt detail around the base, which means the model was printed upside-down. As the bolt detail protrudes out from the base a bit of support material was required under it. Also looking at the doors and vents on the side of the body you can see these were also covered in support material in order to print the base which also projects out further.

This effect is repeated on the rear as shown below.

The second clue is the inside of the model.  In the picture below you can see all the detail is crisp and smooth.  This is because it hasn’t come into any contact with support material.  This is the best finish on the model and sadly it’s the one location where it’s not needed.

The third clue is the actual top of the model.  It should be smooth, like the inside, but as you can see it’s rougher and ‘furry’ with support material residue which has turned into powder because of the Goo Gone.  The whole of the top of the model has been submerged in support material, because the model was printed upside-down instead of the right way up as requested in the orientation setting.

Now, these shells are not bad and the powder residue can easily be removed with a soft brush in a Dremel style tool, or by hand with a brush, leaving you with a good model.  But the surfaces which should have been on top will never be as good as the finish on the inside and areas such as the doors and vents will also be a bit rougher.

So what should it look like? Below is another set of Alco C-855 shells. You can see that after the cleaning process the finish on the outside is not all the same colour. This is because a lot of the surface hasn’t come into contact with support material, as we wanted.

There is still a print shadow effect but this time it’s running down the model and not up.

The doors and vents still have some print shadow but only in a few areas such as the recess for door hinges etc.

The inside of the shell is rougher and covered in print shadow, as we would expect as it was full of support material.

The top is smooth and very well detailed which will show up when the shells are painted.  In the pictures they look rough or lined but this is simply where the Goo Gone has not affected any support material residue and the surface is still a bit transparent.

Hopefully this will help you identify if a model has been printed in the correct orientation or not.  But what should you do if yours arrives and you think it was printed the wrong way up?

Firstly check to make sure the model was designed to have the orientation set. I can’t speak for other designs but my models will state this in the description if it has been set and I can always confirm if you want to contact me and check.  As for the Alco C-855 shells you need to purchase the Deluxe version as it’s not set on the standard.

Secondly, take some pictures of the incorrect model showing things like the print shadow running the wrong way.  Then send an email to Shapeways at service@shapeways.com.  Include your order number, photos and let them know the model you received has not been printed in the correct orientation. Please note: this must be done within ten days of receiving the model.  Their customer service team are quick to respond and will organize a re-print of the model if indeed it was printed wrongly. But again, you only have ten days from the time you receive your print.

As I said before any excess powder will need to be cleaned off and you will find the detail is good underneath it.  You also need to clean this off otherwise any paint applied will flake off as the powder is loose.

You may also be wondering what I’m doing with so many Alco C-855 shells?  These are for a fellow modeller and I’m making a fully powered ready to run A-B-A set for them.  And I intend to share the whole build process with you in a set of posts which should be starting very soon.

Privacy and Materials

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This week I have two things to tell you about and although they are not directly related to trains they are both things which affect my website and 3D printed models.

Firstly I have updated my Privacy Policy and you can read it by clicking here or on the drop down menu below the ‘Contact’ button.  The primary reason for this change is the new General Data Protection Regulation (GDPR) comes into affect on May 25th.  This law is fairly complex but put simply it means that no business or organization can hold any personal data of an EU citizen without their permission.  So I have updated my policy and added a tick box to my contact form as a confirmation that people are happy for me to have this information.  I do however have several contacts for fellow modellers and customers on file, which I only use as contacts for model railway purposes, but if you think you are on the list and would like your details removed then please let me know and I will do so.

My second announcement comes from Shapeways who provide the bulk of my 3D printed models.

They have had a reorganization of the materials they offer and more importantly they have rebranded or rather renamed several of them;

White Strong & Flexible (WS&F) and Black Strong & Flexible (BS&F) are now simply called Versatile Plastic which is available in several colours, including black and white.

Frosted Ultra Detail (FUD) and Frosted Extreme Detail (FXD) are now called Fine Detail Plastic.  This is available in two finishes: Smooth and Smoothest.  Sadly this means the acronyms will be exactly the same so identifying them will be a bit longwinded but they are still FUD and FXD as we know them.  And I can also confirm there is no change in price.

Shapeways have also changed other materials but none which I currently use so I won’t cover them here.  I’ll be working through my products updating the pages for the new material names so please bear with me if you see the old names on any of them.

Next week I’ll have some 3D printed parts to share with you and some advice on how to see if your model was printed correctly.

Installing LokSound Select Direct Micro DCC Decoders in Kato Locomotives

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This week’s post is a guest post; I had one of these before from fellow N Scale modeller Mike Musick who wrote an article about improving Con-Cors N Scale U50s, Turbines, and my C-855 by replacing the wheel sets.  This time the article has been written by N Scale modeller Chris Hatt who has written about installing ESU LokSound Select Direct Micro DCC decoders into N scale Kato Locomotives.

So without further ado, I’ll hand you over to Chris.

LokSound Select Direct Micro DCC (part number 73100)

So, ESU recently released to market three new decoders designed to fit in N-scale “Narrow Hood” locomotives. These are locomotives such as the EMD “SD” locomotives (SD40/50/6070/80 and 90 series) and the GE Evolution (ES44 series), AC4400 and Dash-9 type models which have an external walkway down each side rather than a full-width body shell. The body shells on these models are typically around 10mm wide inside.

The LokPilot V4 Direct Micro OEM (#54650) and LokSound Select Direct Micro OEM (#73199) are both designed to partner recent locomotives from InterMountain and Atlas and are available factory fitted or aftermarket to retrofit DC models. The one of interest to me is the LokSound Select Direct Micro (#73100). This is designed to “drop into many pre-2016 Atlas and InterMountain locos, (and others with minor modification)” (http://www.esu.eu/en/products/loksound/loksound-select-direct-micro/). Many people have been asking on-line if they will fit into Kato N-scale models and there have been few answers. As most of my locomotives are Kato and I favour using LokSound decoders to install sound, I decided to find out.

So what do you get?  In the blister pack is the decoder, two 3mm golden white LEDs and two lengths of fine brown-insulated wire for connecting a speaker of your choice. The card backing of the blister pack is a fold-out instruction sheet (the LEDs and wire are between the halves of the card in a zip-lock bag, not in the blister).

Figure 1: The 73100 from the top. The front-end is to the left.

You will note that there are five pairs of metal pads along the edges of the 73100. The two pairs nearest each end of the decoder are frame power pickups, red to the top of the photograph and black below. The pair nearest the center on the narrowest part of the decoder are not labelled on any documentation but careful investigation with a continuity tester showed that these are duplicates of the motor power pads on the underside of the decoder. The pair of pads inboard of the seconds power pick ups from the right are the speaker connections. The tiny yellowish rectangle on the centre-line at the left end is a surface mount 0402 LED connected to output AUX1. This LED is around 1.0mm x 0.5mm!

Figure 2: The underside of the 73100. The front-end is to the left.

The two big pads under the decoder are the motor drive outputs. The front-most is the “orange” output touching the right-hand side of the decoder. Near the back of the decoder are a +ve supply (DCC “blue”) pad and pads for the AUX3 and AUX4 function outputs. At each end of the decoder are a pair of pads spaced for soldering the LEDs for the head- and tail-lights (F0F and F0R). According to the instructions, there are current limiting resistors installed on all the outputs and standard LEDs can be soldered directly to the pads. The supplied 3mm LEDs are not attached so that you can cut the leads to the right lengths to position them appropriately for the model that you are installing the decoder in.
The tiny yellowish rectangle on the centre-line at the right-hand end is another surface mount 0402 LED connected as AUX2. It will be very difficult to desolder the AUX1 and AUX2 LEDs and reuse the pads, so while this is technically a six function decoder, two of them will be nigh on impossible to exploit unless it is possible to pipe the light using optical fibre.

How does it compare to a Kato lighting PCB?

Figure 3 shows the 73100 alongside the lighting and power PCBs from several Kato models.

From top to bottom:
• The PCB from an SD80MAC (also used in the SD9043MAC).
• The 73100.
• A PCB from an SD70MAC (also used in the early-SD70M, ES44AC, AC4400CW, and several others) .
• The revised PCB used in the “screwless” later-SD70M and the SD70Ace. This board has sideways-facing surface-mounted LEDs in place of the 3mm discretes on the SD70MAC board.

All four have the front-end of the board to the left.  Putting the decoder in my micrometer, it measures 0.75mm thick compared to the 0.5mm of the Kato PCB.

Fitting the 73100 in a Kato early-SD70M frame.

The 73100 is closest to the early SD70M/SD70MAC/ES44AC/AC4400CW part so I started there.

Figure 4: The 73100 offered up to a Kato SD70M frame.

Offering the 73100 up to the frame, it becomes obvious that the increase in width of the board at the rearmost but one pair of power pickups means that the decoder will not fit between the frame halves without easing back the blocks indicated in figure 5 below.

Figure 5: Easing the fit of the waist of the decoder.

Shaving off about 0.5mm from each side with a file, Dremel or milling machine ensures clearance. It does not matter if the fit is snug enough that the pads touch the frame because the exposed pads are frame power pickups.

Figure 6: This nub needs to be made smaller.

The slightly thicker board of the 73100 means that the rounded end of the nub shown in figure 6 that presses on the contact pad at the front of the decoder needs to be trimmed slightly. While the decoder will not drop-and-slide-in like the PCB, it can be trapped between the frame halves as they are assembled and it make good contact and is firmly fixed fore-and-aft.

However, powering up the decoder in the frame caused it to go into a rapid short-circuit/shut-down cycle as shown by blinking of the AUX1 LED. Oops!

Careful inspection showed that there were a number of surface-mounted components that could foul the frame halves and pass track power into the decoder by unwanted routes.

Figure 7: Easing the frame around the front of the decoder from above.

Figure 8: Easing the frame around the front of the decoder from inside the frame. Note the trimmed nub on the right.

Carefully trimming back the frames as shown in figures 7 and 8 removes this contact and everything works nicely. Note that the trim is above and below where the decoder will sit to clear components on both faces of the PCB.

Figure 9: Test fitting the decoder.

As you can see, there is a gap under the decoder at the back into which a speaker could fit, but I prefer an alternate location as shown later.

Adding LEDs and the motor connections

Next, head and tail-light LEDs are soldered to the undersides of the decoder. I think that the supplied LEDs are a bit too “golden yellow” for a modern locomotive so substituted “clear white” ones:

Figure 10: Supplied (left) and replacement (right) LEDs.

Figure 11: Head and tail-light LEDs fitted, AUX3 ,AUX4 and “blue” wires attached and motor feeds in place. The headlight is on but dimmed under “Rule 17”.

I have fitted green (AUX3), purple (AUX4) and blue (+ve supply) wires to the underside of the decoder in preparation for fitting separately controlled ditch lights later. I provided feeds from the decoder to the motor brushes by using strips of phosphor-bronze 1/16th of an inch wide and 5 thousands of an inch thick (1.6mm x 0.12mm) soldered to the appropriate pads on the decoder. These are pressed against the motor brush tabs by the body shell very much like the connections of the original lighting PCB. To prevent these from contacting the frame-halves, yellow “Kapton” tape has been wrapped around the frame rails under their path. In addition, I placed a strip of Kapton tape under the headlight and under the rear of the decoder to ensure that nothing touched the frame there. This is particularly important at the back as the solder joints attaching the purple, green and blue wires would otherwise rest on the frame.

And, of course, a speaker

My preferred location for the speaker is at the back of the frame. By trimming off the shaded area in figure 12, space is made for an 8mm x 12mm “sugar cube” type speaker (although I buy mobile phone spare parts on eBay rather than commercial “railway modelling” speakers).

Figure 12: The bit of the frame I remove to make room for a speaker.
A suitable baffle can be constructed from plastic sheet, purchased commercially or 3D printed (James does some). I attach the speaker baffle to the end of the frame with an adhesive “sticky dot as in figure 13.

Figure 13: The speaker installed.

The baffle provides most of the insulation needed to keep the speaker from contacting the frame but a short length of Kapton tape on the shelf underneath adds to the protection.

And that’s it, bar loading a suitable sound project and configuring the decoder:

Figure 14: A short video of the installation using the “Drive Hold” feature of the decoder to stop it moving while changing the throttle setting. Still got the ditch lights to do!

That is certainly easier than milling out the fuel tank to take a LokSound Micro V4 or LokSound Select Micro and also leaves the locomotive somewhat heavier as less metal is removed:
• With a Digitrax DN163K1C non sound decoder 116g
• With an ESU LokSound Select Direct Micro and speaker 114g
• With an ESU LokSound Micro V4 and speaker 105g
and weight equals tractive effort.

Figure 15: The same kind of frame with a pocket milled in the fuel tank to take a LokSound Micro V4 (or Select Micro), with channels through the back of the fuel tank, across the bottom of the frame and up the sides to get the wires to the lighting PCB to hook the decoder up.

Where next?

Next, the SD80MAC/SD9043MAC and the late-SD70M/SD709Ace.

I leave you this week by saying thanks to Chris for his post and I look forward to his how-tos on fitting LokSound Select Direct decoders into other locomotives.

A Little Holiday to the Dean Forest Railway

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This weekend, as it was a Bank Holiday here in the UK, I decided to take off and visit the Dean Forest Railway in the Forest Of Dean, England.  I’ve written posts about the railway before and you can find one about their 2016 steam gala here.

This visit was not for a particular event but they did have a steam locomotive running and it was an old favorite of mine.  The Great Western Railway small Praire tank number 5541.

Below is a bit of history behind this locomotive (Taken from the Dean Forest Railway Society’s website http://www.dfrsociety.org)

5541 is a 4575 Praire tank engine built by the Great Western Railway. The 4575 class were a popular engine on the GWR, they were versatile and well liked by crew. They were an improved version of the 4500 (or 45xx) class steam engines, the main modification being the larger, sloped tanks.

5541 was built in 1928 at Swindon Works as part of lot number 251. Her original boiler number was 5546. Between June and August of 1930 she was allotted to Swindon shed; however by September 1931 she had moved to Bristol (Bath Road) where she stayed until the middle of 1938. Between December 1935 and March 1936, she underwent general repairs at Caerphilly Works, where she received a new boiler (number 5526). At this time she had covered 237,985 miles.

During the summer of 1938, 5541 moved to Machynlleth where she spent most of the rest of her working life. In the early months of 1945 she underwent general repairs at Swindon where a second new boiler (number 5519) was fitted; 482,639 miles now having been covered. Similarly, over Christmas of 1949 she underwent heavy general repairs at Swindon, necessitating another boiler (number 5505), after 616,385 miles. Another heavy general repair was carried out at Stafford Road, Wolverhampton in July/August 1958, after 839,123 miles. The new boiler fitted was number 3902. During 1960 she moved from Machynlleth to Laira, where she stayed until being made redundant on the 10th July 1962, after completing 921,589 miles.

She was sold to Messrs. Woodham Bros of Barry on the 4th September 1962 as part of Lot L03011/1. Various items had been removed from her between 1962 and 1971, but she had not been moved until being properly prepared for her move from the scrap yard out into the dispatch siding at Barry.

5541 was moved by rail to the Dean Forest Railway at Parkend from Barry, arriving on 10th October 1972 in time for the October Gala Day. Restoration was undertaken by Fund members on the siding behind the down platform at Parkend and was completed, and first steamed on 29th November 1975. On 16th January 1978 in light steam, she joined the movement of stock from Parkend to Norchard and was a regular performer on the short track constructed at the Steam Centre.

On 17 May 1983 she made an historic run over the A48 level crossing in Lydney town centre to collect a large train made up of wagons delivered to Lydney by British Rail. In 16 August 1985 she again went to Lydney Yard to collect the GWR150 exhibition coaches for a weekend display at Norchard.

Following another overhaul and boiler change at Norchard she returned to steam in August 1994. 5541 has made a number of visits to other preserved railways including Bodmin & Wenford, Llangollen, and the Gwili.

The loco boiler certificate expired early in 2004, and the loco undertook a major overhaul until it returned to service in April 2014. During the overhaul, its third on the Dean Forest Railway, the boiler was sent to the LNWR works at Crewe, and the rest of the loco was overhauled at Norchard by our own dedicated crew. The boiler ticket is due to expire in 2023.

Recently 5541 has been overhauled and repainted professionally by Western Steam Engineering at the DFR and I must say she looks amazing.

Here is a short video of 5541 running round its train at Lydney Junction, which is the southern terminus of the line.

And again running round its train at Norchard Low Level platform.  Norchard is currently positioned roughly in the middle of the line, although plans for extension are in hand.

Later in the day I also filmed 5541 doing a little bit of shunting in Norchard yard.

The shunting resulted in the collection of an impressive diesel crane which was built in the late 1950s.  And as this crane, also beautifully restored at the DFR by Western Steam Engineering, is from the western region, seeing locomotive 5541 working with it is very prototypical. Although I don’t think it would have shined as much as this back then!

5541 is regular performer at the DFR and it was a pleasure to see her running again through the forest, even if it was just a short trip over a Bank Holiday weekend.