My printing progress (WAS: My first print attempt)

[mahcr450]

Bryan maybe I missed it in an earlier post.  Could you describe your process for drawing the membrane?  Particularly on the car shell.  It looks like a loft from the car to the base would work but not sure if I'm thinking about it correctly.

Mike

[bbussey]

Make sure the model is at least 6mm from the base plane. Sketch a line on your base plane that follows the perimeter of the model face that faces the base. You can trace the specific perimeter, but I usually inset 0.2mm if possible to provide a visual guide later to remove the model.

Thin-extrude 0.2mm wide, offset 5mm from the base plane up to the model.

On the face of the membrane facing the base plane, sketch a profile 1mm wide and centered.

Extrude the sketch down to the base with an 8% outward draft.

Where the membrane meets the model, if the height is greater than 1mm, thicken the membrane to 1mm. This should leave a 1mm high thin membrane that follows the contour of the model, which also serve as the knife path guide to remove the model from the base.

If the model is fully enclosed (ergo the membrane has no openings), cut 2mm-wide openings in the membrane and drafted membrane support so that the uncurled resin can escape. Make sure there is an escape at the far end of the model as well.

[motofavorite]

Nice detail on the RPO!

[daniel_leavitt2000]

The NYC canstock cars are from PCF, right? I would love to get my hands on a few.

[bbussey]

So after allowing the new magnetic build plate to set for three days, I resumed printing this afternoon. The new build plate is awesome. It’s flexible, so once pulled from the magnetic base, the parts slide off with just a slight flex. Much easier to set up for the next print

I tried the AnyCubic aqua blue resin for the first time. This also is the first time working with standard (non-ABS-Type) resin since I updated the curing lamp and replaced the screen plate.  I ran the first serious attempts of the canstock boxcar and the G32B. Based on the test print, I thought I could get away with a two-second rate, but there are a couple of indications that I have to increase the exposure. I’m rerunning the parts now and will have results in the morning. That said, this first attempt looks very good. They are perfect at the membrane base. Might have to beef up a support and add a couple to the gondola, I’ll know after the current prints are done.

[sd45elect2000]

Bryan,

You have done outstanding work so far! I am curious though how a cylinder would render; I'm thinking of a tank car with surface texture like a wooden vinegar car or a riveted steel tank. How would a steel tank car underframe look?

Just curious is all.

Randy

[bbussey]

I’ve been contemplating that. The frame probably would be best built vertically, with the frame end beams/coupler yoke printed separately.  The tankcar body would have to be printed at 45 degrees to reduce the stepping effects, but they still would be there. I’m going to see if the tankcar wrapper can be printed in the ABS-type resin and then wrapped around a core. Then there would be no stepping in the body and, unlike an etched wrapper, fully detailed relief is possible. But that’s a test for later in the year. Going to try to get the G32B perfected first.

[bbussey]

The NYC canstock cars are from PCF, right? I would love to get my hands on a few.

This version with the canstock-offset Landis doors is a short series and it would be tough to justify having more than one. I’m not even going to decorate one in Conrail. I’m going to paint one in New York Central (non patchout) that lasted well into the Conrail era. I’ve seen only four photos of the prototype, one in CR and three in NYC. I’ve never seen a photo of one repainted PC.

[bbussey]

First attempt at one of the White Tower buildings.  I forgot to put a cutout in the base for the interior.  I also need to add a membrane to all the windows to keep them straight, and add support for under the roof so it doesn't sag.  Not really critical because it's out of view but it looks bad. The bowing on top of the main window may take some thinking also.  It might be that the building will need to be build on its end rather than upright, in which case I'll make the body two parts.



The NYC Canstock car looks good from what I can see.  The triple value and brake pivot rods had issues on the first print, but increasing the exposure time ½ a second fixed those issues.  Had to reprint the ends because my vents for the resin drainage were too small.  I have two sets of bodies and ends to play with and will assemble one before the month is out.



The G32B also had nearly all of it's problems rectified with the exposure time increase, but the vertical posts still are leaning slightly.  I am going to add the extra mass below the car which should even out the FEP forces and keep everything true.



The aqua blue resin doesn't photograph well with iPhones.  It's a deep sky blue color in its true appearance.

[narrowminded]

Quick question @bbussey .  Do you trim the membrane before or after curing?

[bbussey]

I trim the membranes with an X-Acto before curing, it’s easier to do then. Final filing after curing.

[Lemosteam]

I trim the membranes with an X-Acto before curing, it’s easier to do then. Final filing after curing.

As long as you can handle the print without damage, you can skip the filing if you shave the remaining membrane with a pin excpacto chisel blade after cutting it off.

[narrowminded]

And one more @bbussey .  What "normal time" have you been using with Anycubic resin?  It seems that 2 seconds has been working for me with the Anycubic resin in the new Mono machine but that's only a few runs and not larger prints.  I'm thinking of trying these new diaphragm methods on my ND caboose project... when I get back at it.

[bbussey]

Generally 3 seconds but I’ve bumped to 3.5 and sometimes 4 seconds for certain jobs when I’ve had build failures or anomalies or distortion at 3 seconds. I’ve changed my curing screen which is more powerful than the original but also added a protective screen which cuts down the UV intensity slightly. I ended up picking up a half second overall, as I wasn’t getting any good results at 3 seconds and under prior to the curing screen upgrade.

For parts with no surface relief such as your P5a fixture, I could get away with 2-second exposure.

[narrowminded]

Generally 3 seconds but I’ve bumped to 3.5 and sometimes 4 seconds for certain jobs when I’ve had build failures or anomalies or distortion at 3 seconds. I’ve changed my curing screen which is more powerful than the original but also added a protective screen which cuts down the UV intensity slightly. I ended up picking up a half second overall, as I wasn’t getting any good results at 3 seconds and under prior to the curing screen upgrade.

For parts with no surface relief such as your P5a fixture, I could get away with 2-second exposure.

@bbussey And that brings to mind another question.  Sorry.   Do you gat any growth in the wall dimensions at those cure times?  I ask because that's something I had experienced with my original Photon which is the unit I have the most experience with.  The wall dimensions could grow with increased times.  They were consistent so the dimensions could be adjusted where necessary but...