Sunday, March 24, 2013

Roof access, 3D printed for HO scale Model Railroad structures

On most model railroad structures, the roofs are more prominent than the fronts of the buildings.  This makes the roof details important for the visual affect.   

I designed and drew three variations of ladder access roof hatches.  One closed, one open and one with a hatch than can be positioned as desired.

This is the stairs and hatch as it comes from the printer, with the raft and support material still attached, not only to the item, but to the plate items are printed on.  At this point, it really doesn't look like much.

After removal of the extra material, it begins to take shape. 

This close up view, give a better idea of what we are going to end up with.  I have printed a couple of these now, and the clean up quick and easy.

Here are several finished views.  I have yet to install this in an actual structure, but I make a make shift roof to display it. 

I still have several posts in planning stages, including some outside access stairs for structures, pictures of both the finished small engine repair shop and the Barnstead Lumber diorama. 

Monday, March 18, 2013

The learning curve. Using my 3D Printer for HO Model Railroad details

Some of my first prints ended up as melted blobs of plastic.  Details too close together, or entire items too close together.  Orientation of the items is not a particular problem when sending items to shapeways; partly because they are going to orient the item the way they want, and partly because their process is completely different than with the Afinia printer. 

The Afinia is basically extruding a .15mm diameter bead of ABS plastic heated to 250 degree Celsius.  So, first off, you can't get better detail than .15mm.  Second, at 250 degrees, it will melt together any details or surfaces that are close together.  Part of the learning curve was finding out how close together different parts of an item could be without melting everything in to a blob.  Also, what was the smallest cross section that could be printed.  Because there are a lot of variables, this can be a moving point based on the size of the items, how much time the heated head spends in a small area, etc. 

Here is a time lapse done by Christina Chun of an Afinia printer printing a gear key chain.  Although it looks like it prints fast, I would guess this is a couple hours of print time.

One of the first of the larger items I printed was an HO scale elevator tower to sit on the roof of a building.  To print in on the Afina, I broke it up in to several pieces.  Here is an early drawing.  It has a vent on three sides, and they are see through vents, so if you wanted to put a light in the tower, the light would show through the vents.

I broke it up in to four major parts, the walls, the roof, the vents and the door.  Here is a picture of the walls and the roof as they were removed from the printer.  Notice not only the raft that must be removed from under the
print job, but notice all the support material to hold up the walls above the door and windows.

The vents were a great learning experience.  Testing how small the louvers could be, how close they could be to each other, and the thickness of the frames, how they would print, and how the vents would separate from the raft and support material.  Below is a set of windows I did for a scratch build structure addition.  I did not find a picture of the louvered vents as they came from the printer, but this will give you some idea of what it might look like.  The clean-up is similar to cleaning a metal casting, except it is ABS plastic.

Here are a couple shots of a the assemble structure.  It is HO scale, so the actual width measurement is about 1-3/8".  The louvers are a scale 4' square.

Here is the painted elevator tower ready to install on a structure on the model railroad.  The roofing is printed on photo paper from my drawings. 

I did not show all the mistake, prints and reprints.  I would guess the vents were drawn and printed at least four times, the door twice that I remember, and the walls and roof twice.  If I were doing the walls again, I would print them upside down, which would eliminate the support material that was need to support the material above the door.  Also note that the louver vents and door were printed laying down flat, like the windows in the picture above.  In any other orientation, there would be too much support material to remove.

Thursday, March 7, 2013

Time to move to the Afinia H Series Printer

First off, I am part owner of a Afinia H Series 3D Printer.  I went in on it for multiple reasons, which I will list here.  I am not a writer, more of a list maker....

1.  We chose this model/manufacturer based mostly on the review in Make Magazine.  They review about all the 3D printers under in the personal printer price range.  The Afinia was the run away winner in most categories.  In particular, we did not want to buy a kit, and have to assemble it.  I had this unpacked, calibrated and printing in about an hour and a half.  We bought it direct from Afinia, at 
2.  Although as you can see from my previous posts, I could just send everything I design to a third party printer like shapeways, and have them print everything, but the cost of larger items was more than I would be willing to risk.  I say risk, cause so often, things do not print the way you think they are going to, and your money is wasted.  Yes, you always learn from it, but the part is not usable. 
3.  With the Afina printer, the detail/fineness of the printed items is about the same as shapeways detail material, and less than a tenth the cost.  Plus I don't wait weeks to see if the item printed correctly; I get near immediate feedback.
4.  I really like the design process, and having a way to print larger items at a reasonable cost, let me design more stuff.

I looked on line for a good video of an Afinia printer at work, but did not see anything I liked, so I am going to try and shoot my own.  Maybe this weekend.

I describe the printer as squeezing out tooth paste to make an item.  The tooth past must have support, and the software with the printer creates the support for the item that is uploaded in to their program.  In the case of the printer here, the tooth paste is ABS plastic, and it is being heated to over 250 degrees Celsius.  That also limits some of the things that can be done.

Here is a drag line bucket that I have printed in two different sizes.  You can see the support material, as in this case, it all came off in one piece.  Depending on the contact points, the support material my have to be cut off in many pieces.

The smaller bucket, after painting with primer, setting on the support material from the print.

The car is HO scale
  I liken it to cleaning up a metal casting, only since it is plastic, you can use a knife.  The smaller bucket took about an hour to print, and the large one, about an hour and forty minutes.  While  they are printing, I work on other things, like this blog.  I have a bunch of 5' x 5' HO scale louver wall vents printing as I write this.

I have been really impressed with what I have been able to print, particularly the small stuff. Does it have the fine detail of the FUD material from shapways? Well hell no, but it is less than a tenth the price. Here are some comparison pictures.

The blue machine was printed at shapeways, at a cost of a buck or two.  The red machine was printed on my Afinia at a cost of about 8 cents.  Does the blue one have better detail, you bet, but remember how small these are.

These measure less than 3/8" across the base, so sitting in a scene, I doubt anyone would notice the difference in detail.  My pocket book, however, will notice the difference.

Note the rounded corners on everything on the surface of the Afinia printed red machine.  Because the Afinia is essentially extruding hot plastic, it cannot make a sharp corner that small.  Think about trying to make a sharp corner squeezing tooth paste out of a tube.

The desks on each end are items printed a shapeways, and the two in the middle were printed on the Afinia.

Sure the detail is crisper on the shapeways items, these items are about 3/4" wide, and are going to inside an HO scale structure.  In many cases a block of wood would show as well. 
It would not be possible to print the roll top desk on the Afina, again because of the heat generated, it would all melt in to a blob.  Keep in mind those cubbies are probably less than .02". 

I really did not buy the printer to print these small items, so the fact that it will print acceptable items that small for my model railroad is a bonus. 

I will try an learn how to shot and edit video this weekend and get a video up showing the printer at work.  I will be posting many items I have designed and printed for my model railroad.  I will also, occasionally, be showing items that I print at shapeways, because, as you will see in the coming posts, there is a long way to go with this technology, and the $100,000 printer at shapeways can do a lot of things the Afinia will not do.  That said, I am having a blast learning what it will do.  More to come.