[Sbthomas13]

Hey, I know I know, this really has nothing to do with CNC, however, I am planning on building one. Here are some pictures of a dual-purpose screen printer/bandsaw table I built. There is no screen in at the moment, and I still have to devise a way how to make it so I can have interchangeable screens (but that shouldn't be to hard). It has a spring loaded hinge, and the printing area is about 11" x 15". I'll post pictures later of some of the prints I make.

The other shots are pictures of the rest of my workshop. All the tools are Delta Shopmaster, they work pretty well for my needs, however, only the drill press has variable speeds and they can only be accomplished by moving the belt. Also shown is my badger model 155 "anthem" airbrush, a 3 gallon compressor (I will probably upgrade it soon, becasue it can only support light airbrushing) and an automotive spray gun. Also theres just a cool stencil I made of an AK, it was my first stencil ever.

Sorry about some of the unlcear photographs, unfortunatley I was a little anxious to post them so I must have been moving. I'll try to take some more images during the day.

[txcowdog]

I would like to have a small screen print setup also. I look forward to your success in hopes of copying that success and there's nothing wrong with Shopmaster. When it comes to accuracy in a table saw, almost all the time, close enough is good enough. Its not like I'm building furniture for the White House.

[Sbthomas13]

Hey, today I devised a plan for the interchangeable screens. Posted are the pictures of how I constructed the screens in order.

First I cut out the wood for the frame of the screens. I made it so the screens would fit snuggly into the already made frame of the screen printer. I accomplished this by making it so there was a lip on the frame of the screen.

Next I used my compound miter saw to cut the edged wood for the frame into pieces that would fit securly. I made 45 degree angles and fited them together inside the larger frame. I used the large frame as a fixture to hold the sides of the screen in place. I used finishing nails to hold the edges of the frame of screen together, as any larger nails/screws would have split the wood.

Okay, so I now have my frame for the screen completed. It fits snugly into the larger frame (when I use the term "larger frame" I am talking about the rectangular box that is attached to the supporting arm, the one with the handle on it).

The next step is to cut and install my screen. The must common type of screen to use is nylon, I didn't have any nylon lieing around, so I just grabbed a material like nylon so I could represent how to attach it. First, you cut the nylon so it is about 2 inches larger than each side of the inside frame. So now I place the cut nylon onto the larger frame. I then take the inside frame and push it down into the larger frame. This causes the nylon to tighten. Now I fold the nylon up over the edges of the inside frame and staple it down, one side at a time, pulling it tight before stapling it. After I do all four sides, I take the inside frame out. I then staple the inside edge, once again I do one side at a time and I pull it tightly.

Once the screen is stapled down, and it is tight, the build is pretty much done. I have no more construction required, all I have to do now is buy some emulsion and paint.

The emulsion process goes like this:
-First you clean the screen
-Next you use a piece of aluminum channel to spread the emulsion in an even coat on both sides of the screen.
-Let the emulsion dry in the dark

-Next print out the picture that you want to appear, only one color can be done at a time, so isolate the picture to only show one color. Then make the color black on your computer, even if its red in the picture, it has to be black when you print it.
-Print the picture out on a piece of transparent paper.

-When the emulsion screen has dried, place the transparent paper with the desired image on top and tape it down using clear tape.
-Expose the screen, with the picture on top, to sunlight.
-The sunlight causes the parts of the screen exposed to light to turn waterproof, while the parts of the screen under the picture remain unexposed.
-Next go in a dark room and wash the unexposed parts out using a faucet or a hose.
-Attach the screen to the screen printer
-Apply an even coat of paint
-Print!


I will post pictures later of what it can do. Hopefully, the fabric I used will be sufficient....but if not I will have to rip it off and use some nylon.

Please Comment!

[tybrenis]

Looking good, Spencer!

[higgrobot]

Hmmm, I wonder if anyone has mounted an airbrush in their router? .. let me just scribble that onto my things to do list

[Sbthomas13]

Actually, I have thought about mounting an airbrush to the CNC I am planning on building. It would be pretty cool, especially if you were to use a really fine airbrush. The problem I have found is sometimes when you do really fine airbrushing you have to do multiple coats because not enough paint is laided down. However, you could fix this problem by just running the design twice.

Also, if you were doing multiple colors you would have to stop and change the colors. So for small pictures it would be pointless. However, you could do some pretty cool large pictures.

I may be wrong on some of this though, just tell me if you think otherwise. I only recently purcahsed my airbrush, so my experience is limited

[tybrenis]

An airbrush has been mounted in a CNC machine before... if I can find the link I'll show you a CNC mural painter.

[txcowdog]

How do you stretch the screen over the frame to the correct tightness? I have seen the screen being stretched and they use some type of instrument to measure sag in the middle of the frame.

[Sbthomas13]

Actually, I didn't really do the streching proccess correctly. Unfortunatley, I forgot to immerse the fabric in water, which allows for it to stretch better. But on a normal frame (one like mine, with no special places to put the cloth) these are the steps:

Step 1: Cut your piece of nylon so that it is 2 inches larger than your frame on all sides.
Step 2: Immerse the fabric in water.
Step 3: Center the fabric over the frame.
Step 4: Use a staple gun to attach the fabric to the frame using the process of stapleing the middle of one side, pulling fabric taunt, stapleing middle of opposite side, pull it taunt, (do twice)
Step 5: Work from the center of the first side and staple towards the corners, then do the same thing on the opposite side.
Step 6: After a sufficient enough of staples are in (make sure you get the corners) you want to hammer staples in and trim the excess fabric to within 1/2 inches of the staples.

NOTE:
-You want to keep the fabric moist all the time, so have a wet sponge handy.
-Make sure you are constantly pulling the fabric taunt.
-Try to use 200x mesh, its a good, all-around choice. However, polyester mesh works also, and it is readily available at most fabric shops.

And as for tightness, just rub your hand over it and feel for any depressions in the fabric. You should be able to feel any lack of tightness quite easily. Anyways, Im not plannning on doing professional prints, using 8 colors, I'm just doing it for small jobs. I feel confident that mine is tight, but I guess we will have to wait to see. I'm ordering the emulsion soon, so I should have the printing process posted in no time (hopefully).

[txcowdog]

Thanks for the tutorial. I am looking forward to seeing the next steps in this process. Thanks for sharing.

[Sbthomas13]

Heres the new design, the old one took too long to make the frames. This one the frames are simple, and the attachment just uses bolts with thumb nuts.

[txcowdog]

The new design is clean and looks stronger. Will this allow you to change to a different screen faster?

[Sbthomas13]

Yeah, with the new design I should be able to have more structural stability and versatility.

The design involves a simple square frame with four holes drilled in it (I added two more bolts for stability purposes). Additionally the four holes will be countersunk, to make sure the bolt heads dont protrude frome the frame.

The supporting arm will then have 4 holes drilled in it also. Four bolts with thumb-nuts will be placed through the holes attaching the frame to the supporting arm.


This design allows for me to change the screen easily, and also allows for me to change the size of the screen as desired. With the previous design, I was limited to one size screen, because it had to fit into the larger frame. Now I can make the frame what ever size I want.

Also these new frames are much easier to make, being that they require a 2 x 3 with a couple of miter cuts.



This weekend I am going to make a new screen printer, here are the changes:
1) I will incorporate the new frame design
2) It will be a four-color screen printer, meaning there will be four supporting arms on a turn table.
3) The design will be made more stable, because the old one had some play to it.

Also, I will be ordering the emulsion and ink soon. I tried for about a week to find a store that locally sold emulsion, and after checking around 6 stores, none had it. So, I guess I will have to buy it online.

I will make sure I keep everyone updated with the project.

[DigitalMayhem]

Be sure to use a dual cure emulsion that will change color when exposed, it makes things alot easier. Ulano proclaim is a good choice. I use an exposure unit with 9-30w blacklight bulbs with a vacuum top made by Nu-Arc, but building one is not hard, and metal halide lights work very well.

[DigitalMayhem]

-Try to use 200x mesh, its a good, all-around choice. However, polyester mesh works also, and it is readily available at most fabric shops.

200 is WAY too high, 110-150 at most. 200 is for very fine detail and halftones.

[txcowdog]

The one thing that concerns me about a four screen printer is how to set registration on each screen so the image lines up perfectly as it goes around the carousel. It would not have to be off by much at any one screen to ruin the final image.

[DigitalMayhem]

The one thing that concerns me about a four screen printer is how to set registration on each screen so the image lines up perfectly as it goes around the carousel. It would not have to be off by much at any one screen to ruin the final image.

VERY TRUE.

[Sbthomas13]

Wow, I completely forgot about this thread as the build of my Joe CNC has been taking up most of my time. I plan on getting back into screen printing once that build is finished.

As for making a screen printer, my opinion on what the best design is has completely changed. If I was to build another I would use some screen printing clamps/hinges. They are springloaded and allow you to clamp the screen into them. As for the build of a screen, then you would just need to cut 4 pieces of wood with 45 degree angles and glue it up.

Maybe I'll throw something together and try some prints.

[DIY-Guy]

Multiple screens can be aligned with registration pins. Square up the frames, use a long drill bit, drill through all frames down into the table surface. Do this on at least the two front corners, maybe all four. Then insert rounded pegs (point side up) into the holes in the table. When your screen drops down to the table, the pegs will line up the frame.

Brass inserts make it more fancy and precise, but cost more than a hardwood dowel and glue.

Have fun!
DIY-Guy "Currently using creativity to learn CNC routing."

[Sbthomas13]

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