A dispensing needle that’s the wrong bore for the adhesive it’s carrying doesn’t fail cleanly — too narrow and back-pressure spikes; too wide and dot placement accuracy falls apart, and either problem shows up as a defect on the part rather than an obvious equipment fault. Incure’s Sniper™ line covers that selection space with eleven bore sizes across two alloys and five coating options, built to be specified against the fluid rather than picked by habit.
Two Alloys, One Reason for the Split
SN-18 through SN-30 — the larger end of the range, from 1.039mm down to 0.234mm inner diameter — are machined from phosphor bronze: non-magnetic, corrosion-resistant, and the correct alloy for that bore range. SN-6, SN-4, and SN-2 drop below 0.2mm inner diameter, down to 0.057mm at the narrowest, and switch to nickel silver instead — a harder alloy needed to hold bore geometry and concentricity through machining at tolerances phosphor bronze can’t maintain at that scale. The alloy isn’t a branding choice between the two size groups; it’s a manufacturing constraint that only becomes relevant once bore diameter drops below roughly 0.2mm.
Bore Selection Follows Viscosity, Not Convenience
Low-viscosity UV adhesives under 1,000 cP suit SN-18 (1.039mm) or SN-19 (0.859mm), delivering high flow at minimal pump pressure. Medium-viscosity adhesives in the 1,000–10,000 cP range fit SN-20 (0.681mm) or SN-21 (0.610mm). Thicker UV gels and high-viscosity formulations call for SN-23, SN-25, or SN-27, working down to SN-30’s 0.234mm bore for very high-viscosity fluids and ultra-fine dot work. Matching bore to viscosity in both directions matters: too narrow raises back-pressure and slows dispense rate, while too wide sacrifices the placement accuracy the narrower bore exists to deliver.
Five Coatings for Five Different Problems
No Coating is the standard option for most UV adhesives, epoxies, and aqueous fluids. Electroless Nickel adds corrosion resistance and a harder inner bore surface for longer service life with abrasive or chemically aggressive fluids. Nickel PTFE adds a low-friction PTFE-impregnated surface that meaningfully cuts fluid adhesion to the bore wall — the standard recommendation for high-tack adhesives where stringing is a real production concern. Nickel Polymer Type SLK goes further still, the highest-performance stringing-reduction coating in the line, particularly effective at the finer bore sizes for clean break-off with filled epoxy pastes and other high-viscosity materials. Parylene Type C provides conformal, pin-hole-free bore encapsulation with near-zero friction, available on request at specific gauges rather than stocked across the full range.
Email Us with your adhesive’s viscosity and whether stringing is a concern on your current needle, and Incure’s engineers can confirm which Sniper™ bore, alloy, and coating combination actually fits your dispense.
Non-Magnetic by Design
Both alloys in the Sniper™ line are non-magnetic, a real requirement in electronics assembly where a magnetic dispensing tip risks contaminating sensitive components or interfering with nearby magnetic sensors during production. That’s a materials property built into the alloy choice itself rather than an add-on coating, which is part of why the phosphor bronze/nickel silver split holds across the entire size range rather than being available only on select models.
Fixing Stringing Without Guessing
Stringing — adhesive trailing a thin filament after the needle retracts instead of breaking off cleanly — has a specific fix sequence rather than a single silver-bullet answer. Nickel PTFE coating is the most direct remedy, since its low-friction surface promotes clean break-off at the tip. Beyond coating, selecting the smallest bore that still delivers the required flow rate sharpens the break-off point, reducing dispense pressure and increasing retract speed both help, and the Sniper™ line’s tapered-tip geometry itself accelerates break-off compared to a flat-cut needle tip. Combining these rather than relying on one alone is usually what actually eliminates stringing on a difficult high-tack adhesive.
Where the Sniper™ Fits
Electronics PCB assembly uses close-pitch dot placement, edge sealing, and component potting where the non-magnetic phosphor bronze cannula prevents contamination of sensitive assemblies — work that pairs directly with point-of-dispense UV curing on Incure’s robotic dispensing and curing systems. Semiconductor under-fill work on flip-chip packages, BGA components, and die-attach operations depends on depositing high-viscosity epoxy into narrow capillary gaps without bridging or voiding at the package periphery, the same dispensing-precision concern covered from the adhesive side in Incure’s guide to one-part epoxy for robotic dispensing. Optical component bonding uses the ultra-fine sizes — SN-27, SN-30 — for sub-quarter-millimeter bead placement on lens and prism surfaces without contaminating the optical element, a pairing worth checking against Incure’s Optik™ optical adhesive grade guide. Printing and marking work spans the whole range: high-flow sizes handle aqueous inks, while fine sizes manage high-viscosity pigment pastes at consistent dot volume. Jewelry and fine-metalwork applications draw on the smallest phosphor bronze bores, where zero stringing on a high-visibility surface matters more than dispense speed, since excess or trailing adhesive on a finished piece isn’t something a downstream cleanup step can fully hide.
Contact Our Team to confirm the Sniper™ bore, alloy, and coating for your dispensing application.
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