by timbologist Dec 28, 2017
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Have you tried printing in N scale on the Wanhao D7? I'm really curious how it works at that scale. Looks great at HO!

For fun, I tried printing the man at N scale (87/150 = 58%) and I've attached the image. I printed on a CR-10S with a 0.4mm nozzle and 0.06mm layer height. The fellow was almost completely encased in supports but did come out. I was impressed it could do this much. I think I could actually use this print in an out of the way spot or as a torso in a vehicle. But I'm sure the D7 could do something much more amazing!

I'll have to try a smaller nozzle size sometime just for fun.

Hi Cymen

The result of your print is quit impressive despite the nozzle size.
But you will probably encounter problems with your printer because of the number of steps/mm on the extruder is not very many, generally about 100 on direct drive extruder’s so you may have problems using a smaller nozzle.
Attached is a document I wrote for the modelling forum I am on which will explain it with the maths starting on page 5 or post 6.
As for the D7 The problems are that the technology of the printer and the resin prevent you from being able to print very fine detail, fingers are the best example.
If the fingers and the hand are against the body of another larger volume then you get good detail printing, but if the fingers and the hand are away from a larger volume then it is less likely to be able to get good definition of the fingers or any fingers at all. Unless you start to use more energy to cure the resin, which causes over-curing in larger volumes.
The SLA printer that uses a laser gives better finer definition because the exposure energy is constant and is much greater than that of the DLP and DUP printers. I am currently writing a document that explains these difference with all the maths and results of my experimental findings.

If you want to know more just ask


Hi Tony,

Thanks for the PDF. I'm reading that and sharing it with my father who is also interested in this topic. I've been reading about SLA and DLP printers and what you've explained about finger detail in relation to where it is printed is really good information (that I haven't come across elsewhere). Now that you've said that, I pay more attention to miniatures and similar small prints and observe almost all the hands are rendered with fingers together. I'd love to see some prints with fingers and similar detail in the scenario you describe from say the Peopoly Moai. I wonder if it can do it?

I suspect your right about the extrusion stepper. I don't know if Marlin is doing microstepping on it as it is on the other steppers on this printer. I'll dig into that more as I want to know out of curiosity.

Thanks again!

Hi Cymen

Glad the information is of interest to you. I have a CTC Riverside SLA printer which is a clone of the Formlabs Form 1, which can give my quite good detail on fingers and that it has a 0.13mm laser, the Peopoly Moai has a 0.075 laser so is much more capable in this area. But I think the resin would play a major part as well. If a finger is 12.7mm in real world then in 00 scale it is 0.17mm and in N scale 1:148 it is 0.09mm so it is on the edge of not being able to print the 0.09 is only 0.003" so very fine.
With My CTC I am actually running the Formlabs firmware which allows me to run the Formlabs open source software where you can actually change most of the parameters regarding printing, so I can actually change the laser dia, power and speed, so I can fiddle and maybe trick it into printing smaller detail. I have not gone as far as this yet, as I have only just purchased some better resins to experiment with.

Below is a link to a scales converter that I wrote in Java you may find of use, It is hosted on a friends site.

Cheers tony