Dispensing 'glue'/paint

[Pat2000]

Originally Posted by greybeard Pat - I'm reading between the lines here. But re my earlier posting about pva depositing a layer in the tube. If your looking for an adhesive, the "waterproof" type like resinW in the blue bottle(I think) are catalysed so they will glue non-porous to porous surfaces(I use it for non- to non-). These will tend to give the build up that concerned me. However the other type, where your warned not to use them in damp situations, probably wont do this. At least much more slowly I'd guess. If you are only using it as a barrier as in silk painting or glass painting, I'd guess the commercial products like Pebeo are thicker, but not catalysed. I'd be inclined to leave samples in short lengths of whatever tubing you might use for a while and see what happens. John

thanks John, I remember glueing my laminate flooring with the 'blue stuff' thought I'd try and up-grade the glue to give better water resistance - oh boy I struggled to glue em together!! thanks re tubes.

what would you want to do with glue dispensing lots of your fan-shapes?

hey come-on make that m/c bigger !!!

[cbass]

Originally Posted by Pat2000 Cbass , thanks I would have to study those Augers to understand the mechanism better, I'd prefer to make my own pump cos of cost. the Idea I've been toying with is along the lines of what they call 'window clings' thats using window paint see piccys below, the out line (which will perhaps be all i want is made from a black line usually. the Glue they use seems to be based on PVA type of wood glue (the white stuff!!) when it is semi-dry 1-2 hrs, the coloured infilling is added , thats of a runnier viscosity, flexable and semi translucent - its all done on a plastic backing and the 'cling' (rather like a sticker) is peeled off the backing and will self-stick on glass. It is still All plans on the 'back burner' as they say. chances are that I will use my cnc router for all kinds of other purposes lol!! i'm pretty keen also to make a tangential knife It would probably be OTT for me to use a stepper driven auger partly cos of running out of controlable axis, I'm using two steppers on my x axis so thats 4 axis spoken for - a rotary exta axis would almost certainly be one of my future projects. so anyhow if say a small stepper - printer type can be fairly easily driven by a simplish electronic drive all I'd hopefully have to do would be turn it on & off? driving it at a pre-set speed? ... whey-hey boss mans says I can go in to work tomorrow and m/c parts for my router (on a days holiday) so I'm gonna fly me mill and rip-into a few parts!! piccys from http://www.windowbutterflies.citymak...lyGallery.html (site nothing to do with me!)

Pat,

As is often the case, economics determine the type of solution we end up with. The auger type pumps are not cheap. I'm almost positive of this. I just brought them up because I thought they are simple in principle. You may be able to find one from some other application that will work for you. Heck, you might even be able to build one. Its not unlike a meat grinder in design, but you already know that.

Originally Posted by Pat2000 I'd imagined that the auger was also or mainly used to mix 2-part Epoxy glues as they are 'extruded' is that right?

I don't think they are used for mixing, at least not the one I illustrated. If it was, it would be much longer and would require knife blades in-line with the auger to ensure mixing. I think they rely on a seperate mixng machine before it is fed to the auger...

Originally Posted by Pat2000 just found this on auger pumps - all a bit OTT (over the top) for my application but interesting for those following this - they reverse the auger slightly to stop/relieve pressure at the nozzle!!

Thats whats so cool about this design. It has very precise control as rotary motion is translated into linear motion. A lot of similarities to why ball/lead screws are so great.

Carlo

[Pat2000]

Originally Posted by cbass Pat, As is often the case, economics determine the type of solution we end up with. The auger type pumps are not cheap. I'm almost positive of this. I just brought them up because I thought they are simple in principle. You may be able to find one from some other application that will work for you. Heck, you might even be able to build one. Its not unlike a meat grinder in design, but you already know that. I don't think they are used for mixing, at least not the one I illustrated. If it was, it would be much longer and would require knife blades in-line with the auger to ensure mixing. I think they rely on a seperate mixng machine before it is fed to the auger... Thats whats so cool about this design. It has very precise control as rotary motion is translated into linear motion. A lot of similarities to why ball/lead screws are so great. Carlo

Thanks Carlo Thats great... its all good info that we can pick up ideas from, I'm not sure how those augers work quite, I'll look into them if I get to it.. yes precise feed - name of the game thanks again

[fyffe555]

late to the game here but how about using a Peristaltic pump on a stepper motor so the speed could be controlled, but don't pump the adhesive directly, use the pump to pump water in a closed system on the glue side and use the water (since water is incompressible) to pressure the back side of the glue container like a caulk tube. You could apply glue then reverse back so taking pressure off the glue dispenser.. Not much pressure needed, think caulk gun, with a bit of playing I'm sure you could get incremental Gcode sorted to advance the pump for so much glue, timed with the xy motion and then reverse the stepper a bit to stop...

[kdoney]

I used an efd dispenser. The connection to the foot pedal was operated by a relay from Campbell Designs Parallel port breakout board being run from Mach 2. I was creating stained glass windows (acrylic). Everything worked fine until I wanted to fill in the colors. I couldn't find an acrylic which would dry transparent and still have the viscosity to settle in the outline of the liquid lead.

[CLaNZeR]

I purchased one of these for dispensing exact amounts of solder paste onto PCB's for surface mount designs and I was amazed at the accuracy of the shot delivered when timing and pressure set correctly to suit the consitencency of the paste.

http://www.intertronics.co.uk/products/cjbe1113.htm

I used it for solder paste on PCB's manually at first and then attached it to my CNC machine, I have to update the web pages showing it when I get a minute.
I control the pedal by wiring it into a relay which is switched via the controller box and controlled by pin1 of the parallel port.

I have only got a 100PSI compressor, which is fine but I did find that I had to slow the machine down a bit so I did not loose the pressure to much by fdoing to many pads at once and hence end up with less paste than what I wanted.

Regards

Sean.

[vfsi]

In a previous life I built a RTV Silicone glue dispenser for a medical product manufacturing line. The bead size tolerances were very tight. And the glue needed to be in a circle at the bottom of a 3in x 3in cup.

I used a pneumatic caulking gun to preload a small gear pump connected to a DC speed control gear motor (~100 rpm). The controller had regenerative braking so it stopped quickly. I had to anticipate the extra flow but the thing was reliable as a rock.

I was told it wouldn't work, by many experts. Just goes to show, those that don't know any better just do it anyways.

Find the stuff on ebay for a cheap solution.

[kevinsull56]

We had been using pneumatic dispensers for dispensing micro dots of paint for years until I found this air free dispensing system. They offer several different types of dispensing systems for assembly.

This is what they say:
Control and monitoring of a consistent repeatable assembly fluid deposit worldwide resulting in increased bottom line profits through higher productivity, fewer rejects, less fluid waste and lower production costs.
See fishmancorp for more details.