视觉点胶机Z轴高度怎么调？

1. What Is Z-Axis Height

The Z-axis height of a dispensing machine is the vertical distance from needle tip to product surface,known in the industry asneedle gap. This seemingly minor distance directlydetermines the shape, position and size of the glue dot— too high and the dot shifts or splatters; too low and the needle scratches the product or clogs. Z height must be recalibrated after every needle or product change — the most basic yet most overlooked step in dispensing setup.

2. Consequences of Too High vs. Too Low

When the needle gap is too high, adhesive travels a long distance to the surface; gravity spreads it sideways, causinglarger, irregular-edged glue dotsand, in severe cases,splashing that contaminates non-target areas. When the gap is too low, the needle nearly touches the surface; insufficient dispensing space leads tosmaller dots and uneven glue buildup, and more dangerously the needle mayscratch the product surface or bend and clog on product edges.

3. How to Adjust: From Coarse to Fine

Z-height tuning takes two steps.

First, coarse adjustment: lower the needle close to the product surface, fine-tune Z on the computer, and measure the gap between needle and surface.

Second, fine adjustment: run test dispenses and inspect the dots — irregular edges mean the height is too high, scratches on the surface mean too low. Adjust gradually until dots are regularly shaped and uniform in size.

During tuning, adjust dispensing time and air pressure together — the three parameters interact.

4. Matching Different Adhesives and Needles

Z height is not isolated; it is closely tied to adhesive viscosity and needle type. High-viscosity adhesive has high flow resistance, so the needle gap can be smaller, letting the needle guide adhesive onto the surface; low-viscosity adhesive flows easily, so the gap should be slightly larger to prevent over-spreading. Needles differ in stopper design — some have built-in stops guaranteeing the same descend height every time; needles without stops need Z-height calibration before every startup. Adhesive temperature also affects the gap — the ideal working temperature is 23-25°C; lower temperature raises viscosity, reduces flow, and requires gap and pressure adjustments.

5. Z-Axis Countermeasures for Stringing and Dripping

Stringing is a common dispensing defect directly related to Z height. Slow needle retraction after dispensing and too-small gaps both worsen it. Countermeasures: increase the needle gap, speed up retraction, and set a delayed retraction so the adhesive breaks before the needle rises. For high-viscosity adhesives, add suck-back at the needle end — an instant negative-pressure draw after dispensing cuts the glue. Dripping is the opposite: when the gap is too large or pressure too high, adhesive seeps even when not dispensing; reduce pressure, check needle wear, and narrow the gap.

Boli machines use air-driven dispensing with a needle that never touches the product; Z height is set precisely on the touch screen, assisted by the vision positioning system.

6. Summary

Z-axis height directly determines glue dot shape and positional accuracy — too high causes splatter, too low causes scratches. Tune from coarse to fine, adjusting dispensing time and air pressure together; recalibrate on every needle or product change. For stringing, raise the gap and speed up suck-back; for dripping, lower pressure and narrow the gap. Treat Z height as a routine check and dispensing quality stays stable.