Stainless Dispense Nozzles
Overview: Designed for high volume dispensing applications for solder paste, Surface Mount Adhesive, Underfills, sealing, gasketing, flux, dam and fill and other component and board level dispensing. This nozzles are internally conical to improve flow. Held to tight tolerance, they exceed the OEM nozzle quality and consistency.
Construction: Using a single piece of stainless steel the nozzle is cut to a mathematical model with a milling process. Unlike other nozzles where each is hand made, the nozzle to nozzle consistency is excellent. This means much less set up time and every nozzle dispenses and flows the same. The interior fluid path is smooth and tapered. The single piece and tapered design removes the transition point between an inserted surgical tubing and a hub found in older and cheaper designs. This improves flow and makes cleaning easier. The stand off post is a separate piece placed in a hole with an interference fit.
Adaptation to different valve brands and styles can be done in 2 ways: 1) with an adapter and 2) a matching hub design to fit just like the OEM nozzle. Please specify brand and model of dispenser. It is best to send a spent nozzle for verification.
Features and Advantages
- Stand off. The stand off is normally used to control the gap between exit port and the substrate. Normally dispensing dots of Surface Mount Adhesive, solder paste or other dots with out a Z-height sense requires a stand off. If this is too low, material can stick to the area around the exit port and cause stringing. If it is too high the dot does not form a good base and stringing also occurs. If the position is incorrect the stand off post can land on metalization of buried traces or other board features that are a little thicker than normal and change the dispense gap. Proper placement normally means placing the post at a certain angel and distance from the exit port. Normal placement is at 0, 45, 90, 135, and 180 degrees. The distance is normally about 100 mils (2500 microns) from the center line. When ordering you have the ability to change and specify these features.
- Wear – Wear occurs in 2 areas. 1) The exit port can become larger if abrasive materials are being dispensed. 2) If a stand off is being used, the stand off gradually wears down. This material exhibits excellent wear resistance, but 2 types of stainless steel can be specified to offer different resistance to wear. Additionally a hardened stand off can be ordered. Normal posts are 30 mils (750 micron) in diameter – this thinness offers increased wear resistance.
- Tip configuration. A normal 45 degree taper is the default offering. Different configurations are available on request. For example the end close to the exit port can be thinned for die clearance in underfill applications. It is also possible to create an oval opening to maximize the adhesive dot shape and fit into narrow areas.
The wide open conical design on the inside and a relatively short narrowing around the exit port make cleaning easy. Recommended cleaning solvents vary by the materials being dispensed, but examples include.
- Example #1 Remove as much as dispense material as possible with acetone and a squeeze bottle, with paper towels. Then place the nozzle in a beaker filled with solvent. Then place the beaker in an ultrasonic bath and leave for 10 minutes. Remove and dry the nozzle.
- Example #2 Using the solvent recommended by the manufacturer (this is often called a thinner and is a part of the material formulation for viscosity adjustments) run the solvent through the valve / nozzle until there is no color change (it runs clear), then clean as recommended in example 1
The death of a nozzle: Normally the way nozzles become unusable is not wear. Nozzles are normally damaged or have curred adhesive inside or around the exit port. Proper care and cleaning can dramatically cut nozzle replacement costs due to cured adhesive. One of the more common problems is the use of IPA (Isopropyl Alcohol). This cleaner contains water. The water promoted the curing of the adhesive. It is a solvent normally best to avoid for this operation. The open internal design easies cleaning, the harder stainless resists damage. Damage can occur in many form, but one of the more common types are damage on or around the tip of the exit port during cleaning. This area is extremely precise and it represents one of the thinest, most easily nicked, bent, or distorted areas. Once damaged, the dispensed material can conform into or around the damaged area causing inconsistent dispense or stringing problems, or preventing a clean break off (poor quality line starts and terminations). Care and inspection helps.
Cheaper nozzles are availably, but with proper care, a better (more expensive) nozzle can dramatically reduce the overall cost. The conical shape easies cleaning, the harder stainless prevents damage and wear is reduced. One high quality nozzle can outlast 2 or 3 lower quality products. Also the dispense results are easier to obtain and maintain.