Author: thoromyr, published on 2013-07-09
This is a set of coins for use as props with a role playing game and covers the gamut from 1/4 copper to double gold (this is not for a gold inflated economy) in rough mimicry of the old LSD coinage with a 50-coins-to-the-pound rule. They are sized for relative density of the notional metals involved. The current test prints are in red, but the intention is to use red for copper, white for silver and yellow for gold.
UPDATE: the provided “silver coins 166s.x3g” may be useful to someone with a replicator2 — it fills most of the build plate with silver coins (I have too many issues with peeling near the left or right edges to be worth getting close to them) amounting to 166 shillings worth (32 quarter, 16 double, I think 16 half with the rest being 1sp). This takes ~12 hours to print. The “silver coins 64s.x3g” uses even less of the build plate, takes about 6 hours to print, and is comprised of 64 quarters, 32 halfs, 16 1sp and 16 doubles.
IMPORTANT: after validating the meshes and getting successful prints I posted this. Then some subsequent prints failed, and on checking somehow there were holes in the mesh of some objects. I have no idea how that could’ve happened, but it did. The contents of the “MintMarked.zip” archive has had all obj files validated by netfabb and so hopefully there are no mesh errors.
IMPORTANT: Using Makerware and Replicator 2, reliability of printing is substantially improved by lowering the temperature. I have used 225 degrees with good success. Printing a sizable number of coins at the standard temperature frequently results in stopped extrusion.
A feature of makerware is the use of “bridges” — thin strands of filament between objects to help improve their stability. These have become more prominent in recent versions of makerware causing prints to be hairy and making a hash of the features on the faces. The best thing to do is disable bridges which requires creating and editing a custom profile. The “CoinProfile.zip” file contains just such a profile otherwise using standard settings.
The dimensions of coins are not a good fit for fused filament fabrication: stamped metal coins are too thin when replicated in plastic. Consequently these are thicker than they “should” be. The individual object files are “properly” sized for material density, but the “thing” file has some rescaling done to better suit the needs of printing on a Replicator2.
Coins are sized in mm in the object file and so come in at the “correct” size. They each load in their “own” spot, but flat as that is how I built them. For printing I put them on-edge and the thing file has them in this orientation. If you just want to see what they look like load the thing file (though for printing you will likely want to at least duplicate the largest coin — see issues below).
The most successful prints have been with default medium settings. Printing on the high resolution and/or with one shell and 100% fill has at best not improved the results. An earlier version of this was printed directly on the build plate without a raft or supports. I find with the red plastic I get better adhesion (and more reliable results) using a raft and the new support structures provides all necessary support without overdoing things.
Printing the coins larger than sized will allow better viewing of the detail. They don’t photograph particularly well so they have more detail than may be apparent from the pictures, but they look better larger.
The “mint mark” coins each have a fictitious mint’s “mark” on them. The 1/4 and 1/2 size coins have also been enlarged to improve printing results.
I have not been able to get the small coins (particularly the 1/4 gold and 1/2 gold) to print reliably and although the printer goes through the motions, extrusion always stops after the next-to-tallest piece is completed.
In mixed batches like the thing file the top of the 2 copper coin never prints. Although I haven’t done a print to test it with these coins, when I’ve encountered this before it satisfied to simply have two of the tallest item for extrusion to last through the entire print. For production runs of the coins I plan to just fill the build plate with a single coin and go.
License: Creative Commons – Attribution
Tags: carrara, rpg