Palmerston - Small England Loco as built

[Trevor Thompson]

Yet another 3 D printed project.

There are drawings of the early Ffestiniog locomotives in th e16mm Association special edition covering the early Ffestiniog railway. As usual I have scanned the drawings and imported them into Sketchup. I have moved them around and orientated them so that they form a grid from which to draw the locomotive. I can then draw guide lines so that their intersections show the outline of each component as I create it. Each component is saved as a "component", partly so that subsequent drawing does not alter the component already drawn, and partly so that I can identify the sub-assemblies I am going to try to print as one piece on the printer. Here is the drawing:

Screenshot 2023-11-27 at 12.49.25.png (736.8 KiB) Viewed 5110 times

This is my first attempt to use bigger build area of my Anycubuc Mono X2 resin printer to create a locomotive. The plan is to print as much of the loco as a single piece as I can - to avoid gluing things together.

So the first main component, the chassis complete with the mounts for holding the motor (or motors if one is not powerful enough):

IMG_3504.jpeg (2.04 MiB) Viewed 5110 times

Trevor

[philipy]

Looking good Trevor.
I do envy you your ability to use the 2D drawings in Sketchup, I've tried to do it myself but without any real success. I guess its some sort of knack which I haven't yet found.

[Trevor Thompson]

Looking good Trevor.
I do envy you your ability to use the 2D drawings in Sketchup, I've tried to do it myself but without any real success. I guess its some sort of knack which I haven't yet found.

It was just a matter of perseverance. I don't give up easily! Well I gave up twice but went back to it again.

Trevor

[Trevor Thompson]

I have found the large resin printer a challenge - in some ways. Firstly each attempt at a component uses a lot of resin - and there is always something which could be better if I made it again.

My first attempt at the chassis had the motor mounts integrated into the chassis but at an angle. I also used the mounting holes in the end plate of the motor to fix it to the chassis. Both were in error. Using thew screws means that the gear has to be removed before the motor could be attached or removed. Unfortunately the small nylon MOD 0.5 bevel gears were press fit - so not easily removable. Secondly I couldn't actually get the motors into the holders - one went in but the first was in the way when fitting the second.
So I have modified the motor mount by making the hole in its lower end big enough for the gear to go through. Now the gear can be bonded to the shaft and then the motor fitted. I have just secured the motor with a dab of LockTight. Hopefully it will come free if necessary - and hopefully it won't come free unless I want it to.

Organising the orientation for printing larger components, and getting the supports right, is a separate issue. For this chassis I printed it parallel to the bed, upside down, using "medium" supports. That leaves the remains of the supports on the top of the chassis which will be out of sight:

Screenshot 2023-11-27 at 16.04.57.png (90.02 KiB) Viewed 5088 times

I was a bit concerned that the print might pull off the supports but if I look at the area that the printer is going to print at a single moment it looks like this:

Screenshot 2023-11-27 at 16.30.27.png (18.61 KiB) Viewed 5088 times

and this is the layer that it would be printing at that time:

Screenshot 2023-11-27 at 16.30.11.png (137.73 KiB) Viewed 5088 times

I hoped that would not be enough to make it stick to the bottom of the tank - and pull off the supports.

Trevor

[Trevor Thompson]

So it worked.

I printed coupling rods, wheels, and connecting rods on the smaller printer which I have. The coupling and connecting rods had holes for bushes - trying to make a more "professional" job of it. I have bored and tapped the wheels to take stainless crankpins. So the chassis assembled:

IMG_3513.jpeg (1.77 MiB) Viewed 5087 times

IMG_3511.jpeg (2.01 MiB) Viewed 5087 times

I have made the crank and connecting rods the correct round tapered profile - I think its an important feature of this loco - I just hope they are strong enough.

You can see the coupling rods fitted , and the motion turns reasonably freely - I think it just needs running in. The coupling rods are lying alongside in one of the photos ready to fit when the footplate is printed. The thickness of the coupling rods is taken up on the rear wheels by washers for now. You can also see the grey "wheel" on one axle which carries 4 magnets which will trigger the sound card (eventually).

The footplate raises issues which I will describe in the next post!

Trevor

[Trevor Thompson]

To give an idea of how I plan for the chassis, footplate and motion to fit together a screen shot:

Screenshot 2023-11-27 at 19.12.26.png (314.7 KiB) Viewed 5075 times

The chassis fits into a slot in the footplate and is secured at each end with bolts and brass bushes bonded into the footplate. The cylinders and slide bars are separate subassemblies which are printed as part of the footplate. I don't want to have to glue them on. The crossheads are printed as separate items and slide freely when everything has been cleaned up with a needle file. My first attempt at the footplate:

IMG_3506.jpeg (1.7 MiB) Viewed 5075 times

IMG_3505.jpeg (1.79 MiB) Viewed 5075 times

Bear in mind that I thought the motors would sit inside the chassis and not protrude into the body - where I want the batteries to go.The chassis did actually fit in there after some judicious filing but I had difficulty getting the wheels and coupling rods and nuts to clear inside the crossheads. Everything was just too wide. So in the re-design I moved the cylinder assemblies 1mm further apart. Also I made holes for the motor mounts to protrude through.

I have in the past had to make my models in a number of parts - for example the side of a coach might have been in 4 sections. I was keen to try to make this footplate in one piece. The only way this would fit into my printer was like this:

IMG_3510.jpeg (1.54 MiB) Viewed 5075 times

In preparing to re-print this footplate I added "heavy" supports rather than "medium" supports and in retrospect I think that was unnecessary because at an angle like this there is not a large area being printed at any one moment:

Screenshot 2023-11-27 at 21.13.12.png (310.68 KiB) Viewed 5062 times

Partly because this printed unit only just fits into my washing tank, and partly because of the heavy supports the end of the footplate closest to the raft was particularly hard to remove. This resulted in some chips missing from the end edge of the footplate. I also failed to notice that some of the supports were actually touching the model in places - that resulted in the stays on one side of the firebox being lost, because I had to file the supports off. A pitty but not worth the expense of reprinting it. Getting all those stays free from the footplate also took ages.

Trevor

[ge_rik]

Those prints look remarkably crisp.
I might try a few more on my resin printer

Rik

[philipy]

I'm particularly impressed by the finish on the top of the footplate. If I'm seeing things correctly, the top of the footplate is the underside of the print and has the supports? There appears to be very minimal dimpling from the supports and relatively few visible layer lines - or is that simply because you've sanded it all out?
I find that I need quite large support connections and lots of them, and I still get all sorts of sagging and bulging. When printing things that big I wouldn't dare to print without heavy supports.

IMG_0502.jpg (255.49 KiB) Viewed 5023 times

[SimonWood]

Really useful thread. I must post about all the problems I am having with resin printing, and I would not have even attempted your chassis orientation for fear that supports would be insufficient to pull that much surface area off the FEP. So it's really good to know that's possible.

I am curious why print the chassis in resin? Most of it will not be visible - did you consider just printing the end details in resin, and the structure of the chassis in filament? At this point that is what I would have done - I could tell myself it is because filament prints are relatively strong, rigid and light, but in truth it would be because it saves me printing one more thing in resin...

[philipy]

Simon, my picture above is of one of the prints I did in my DeWinton build. I can't speak for Trevor, but my reasoning was the ability (potentially) to produce all of the detail in one go without having to put all the fine detail on individually. This is a one piece print but the underside looks like the previous picture!:

DSC_0003.JPG (412.54 KiB) Viewed 5003 times

[Peter Butler]

Philip, that DeWinton is most impressive. I have always been critical of the striations left from filament printing but your resin print is superb.

[Trevor Thompson]

I'm particularly impressed by the finish on the top of the footplate. If I'm seeing things correctly, the top of the footplate is the underside of the print and has the supports? There appears to be very minimal dimpling from the supports and relatively few visible layer lines - or is that simply because you've sanded it all out?
I find that I need quite large support connections and lots of them, and I still get all sorts of sagging and bulging. When printing things that big I wouldn't dare to print without heavy supports.
IMG_0502.jpg

Yes the top of the footplate has the supports - well most of them.

There is as you say almost no sign of dimpling. The ball shaped remains of the supports need filing away but it is otherwise not a bad finish. Not perfect but usable. I think the key to printing large flat areas is to print them at an angle. More to add on this shortly.

Trevor

[Trevor Thompson]

Really useful thread. I must post about all the problems I am having with resin printing, and I would not have even attempted your chassis orientation for fear that supports would be insufficient to pull that much surface area off the FEP. So it's really good to know that's possible.

I am curious why print the chassis in resin? Most of it will not be visible - did you consider just printing the end details in resin, and the structure of the chassis in filament? At this point that is what I would have done - I could tell myself it is because filament prints are relatively strong, rigid and light, but in truth it would be because it saves me printing one more thing in resin...

There are a number of factors which influenced trying this in resin. Firstly to see what this technology is capable of, and if I can make it work. Secondly I want to avoid joints on the side of the footplate, which are difficult to hide. Partly I am influenced by seeing things made in one piece for smaller scale railways, such as the one piece buildings David has which are made for 7mm scale.

I didn't think of combining the technologies, the build volume of this resin printer is bigger than that of my filament printer. At the moment my filament printer is fully engaged in making a castle. I am also influenced by the issue of glueing the parts together. I can glue filament prints together with solvent, but how to join resin to filament successfully?

Trevor

[Trevor Thompson]

I now have the footplate reprinted, cleaned up and connected to the chassis:

IMG_3514.jpeg (2.13 MiB) Viewed 4973 times

IMG_3515.jpeg (2.52 MiB) Viewed 4973 times

I am using one of those geared motors, which seem to be very powerful for their size - and of course have a second standing by in case it isn't powerful enough.

The top of the footplate has been filed to clean up the remains of the supports. The bushes are fitted and the chassis is bolted to the footplate. I have by the way been running it up and down the test track - so it works so far.
The connecting rods need bushes, and fitting. The crossheads also need holes and mock piston rods fitted. So that is the next job.

You can see where the rear footplate was damaged removing the supports. I have yet to repair that. Also at the front there are the remains of supports which were added automatically to support the front lip of the footplate. I am not convinced that it actually needs supports in that area. Both surfaces were at 45 degrees to the bed - so surely supports were unnecessary there? I have been removing supports and I will experiment further with that.

Trevor

[Trevor Thompson]

I have made a couple of attempts at printing the body.

My initial attempts to slice the whole body as one part were unsuccessful as the slicing software couldn't handle the data density. So I tried just the tanks and peripheral bits:

IMG_3508.jpeg (2.32 MiB) Viewed 4966 times

I did set this at an angle with the front up in the air - the result isn't perfect - lots of supports stuck to the sides. It also highlighted that some parts were too thin. A disadvantage of working from the drawings as I do is that I inevitably make the part to scale (and that makes it too thin). I have to go back and increase the thickness of the support for the pressure gauge, and the guards around the footplate.

I decided that I would get better definition on the name plate and particularly the makers plate by printing at an angle - side to side. So to avoid the under side being disfigured by supports I split it in half. The second attempt is here:

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IMG_3518.jpeg (2.44 MiB) Viewed 4966 times

The writing on the makers plate is perfect now, but look at the distortion on the bottom edge. Bowed. Unusable.

However I think I am working in the right direction. I think that the issue is that I chose the wrong angle. I will try again with a different angle and make sure the inside of the sides are well supported and closer to the build plate like this:

Screenshot 2023-11-28 at 11.53.20.png (180.82 KiB) Viewed 4966 times

Perhaps the problem is that balance pipe at the front which raises the whole thing up in the air.

Trevor

[SimonWood]

the build volume of this resin printer is bigger than that of my filament printer.

Same here. I have been, just for comparison, printing the parts from Rik's GVT wagon on both printers. On the filament printer I need to cut the wagon side and then reassemble, and it's a visible part. With resin, not only is the detail crisper, it's all one piece. (But is snapped - because brittle!) However, for a hidden part like a chassis I've been less worried about the one-piece issue, since welding ABS with acetone produces a strong bond and visually it doesn't need to be perfect.

I am also influenced by the issue of glueing the parts together. I can glue filament prints together with solvent, but how to join resin to filament successfully?

How do you join resin to resin?

I've been using superglue. Which also glues the resin to filament. I don't like it, but I'm not sure what else to use.

[Trevor Thompson]

the build volume of this resin printer is bigger than that of my filament printer.

Same here. I have been, just for comparison, printing the parts from Rik's GVT wagon on both printers. On the filament printer I need to cut the wagon side and then reassemble, and it's a visible part. With resin, not only is the detail crisper, it's all one piece. (But is snapped - because brittle!) However, for a hidden part like a chassis I've been less worried about the one-piece issue, since welding ABS with acetone produces a strong bond and visually it doesn't need to be perfect.

I am also influenced by the issue of glueing the parts together. I can glue filament prints together with solvent, but how to join resin to filament successfully?

How do you join resin to resin?

I've been using superglue. Which also glues the resin to filament. I don't like it, but I'm not sure what else to use.

So have I. It isn't my favourite either. In fact I think getting it on my skin has inflamed latent dermatitis. The only other thing I can think of is quick set epoxy.

Trevor

[philipy]

How do you join resin to resin?

I've been using superglue. Which also glues the resin to filament. I don't like it, but I'm not sure what else to use.


So have I. It isn't my favourite either. ... The only other thing I can think of is quick set epoxy.

Me too, on all counts.
So far ( fingers crossed) I haven't had a resin-resin or resin-filament superglue joint fail, the resin is more brittle than the joint, I think.

I've never tried it but I have thought about using resin as the adhesive...paint it on the parts to be joined, tape them together and stick it back under the uv light. I guess it might be a problem with black or other opaque colours but could work with translucents?

[-steves-]

In fact I think getting it on my skin has inflamed latent dermatitis.

Trevor

Are you 100% sure this is the superglue and not the resin? I only ask as resin completely screwed up my hands for 10 months, cracking bleeding etc etc, really really nasty stuff. Apparently it goes through nitrile gloves and the like in less than a minute. I only use marigold type gloves when dealing with resin now until it's totally cured and dried.

[Trevor Thompson]

In fact I think getting it on my skin has inflamed latent dermatitis.

Trevor

Are you 100% sure this is the superglue and not the resin? I only ask as resin completely screwed up my hands for 10 months, cracking bleeding etc etc, really really nasty stuff. Apparently it goes through nitrile gloves and the like in less than a minute. I only use marigold type gloves when dealing with resin now until it's totally cured and dried.

Yes I have been trying to work out which is the cause for some months. I think the industrial superglue is a problem in itself when it gets onto skin. Moreover I am sure that I have been suffering from contact with the resin as well. Made worse by a tendency to scratch - thereby transferring it to my face. I wasn't aware that it could get through disposable gloves so quickly, but I have been buying disposable gloves specifically described as for use with chemicals. I think I will try some of the thicker gloves for chemicals!

Trevor