This Syringe Adapter Head fits 50/60cc syringes commonly found in medical applications and can be used in air pressure dispensing applications or in paste extruders for 3d printing. It also makes a great replacements for the Makerbot Frostruder syringe adapter. With a quarter of a turn it locks and seals the syringe so you can use air pressure to dispense its contents.
The adapter head consists of one part only and should be printed with support material turned on. The bolts you see in the various pictures are not used to assemble the parts but to prevent the adapter from delaminating and flying apart under pressure. The bolts are there for reinforcement.
There are other adapter heads on thingiverse but they use extra o-rings or tube connectors which are not needed in this design. Instead of an o-ring I use the rubber plunger that comes with your syringe as a seal, the tubing is friction fitted.
Update June 18, 2013:
Added an extra strong version, two extra bolts to relieve stress. Thicker top and bottom + extra reinforcement beam on the top.
I use this adapter with BD plastipak 50/60cc syringes, similar sized syringes from other brands will probably work too, leave your experiences in the comments and specify brand and type so I can add them to this list:
-BD plastipak 50/60cc
I have operated this Syringe Adapter Head and standard medical syringes at pressures up to 6 bar for over a year without issues but I guess this is close to the limit of what it can take. Your millage may vary depending on the quality of your print and syringes and I am NOT responsible if stuff explodes and harms you, your family, your dog or anything else around you.
-Print out the part SyringeAdapterHead.stl, you will need to print it with support turned on. Carefully clean the part by removing the support. There is no need to seal the part (acetone/glue...) because the syringe is sealed by the rubber plunger cap.
-Drill out the 3mm holes and add 3mm bolts of sufficient length. Add washers on both sides, don't use 3mm washer but try to use larger ones that are still hold by your 3mm bolts head.
-I use PL-4 tubing from FESTO that I found at bargain price, you can probably find similar stiff pneumatic tubing normally used in air pressure applications. Inside diameter is 4mm, outside is 6mm.
-Check if your tubing fits the center hole, it should take some force to get it in because it should withstand the pressure by friction only. If the hole is to small, file or drill it larger but be careful not to stretch it to wide. Let the tubing stick out 5-10mm.
-Take the black rubber piston from your syringe and make a tiny hole in the centre with a small drill or sharp pointy knife, now pierce the short end of the tube trough and fit the rubber on the syringe adapter, twist a bit back and forth so it fits nicely.
-Test by closing a syringe (old clogged needle,...) and gradually increasing the pressure, the adapter can bend under high pressure but should hold (see picture). Wear safety glasses when testing.