US-20260124637-A1 - NOZZLE BOTTOM POOL DETECTION METHOD AND DEVICE

US20260124637A1US 20260124637 A1US20260124637 A1US 20260124637A1US-20260124637-A1

Abstract

Problem: To provide a technology that enables easy and highly-accurate determination on a pool that has occurred at a bottom end of a nozzle. Solution: Provided is a nozzle bottom pool detection method in a liquid material discharge device, the method including: a first process of moving a nozzle 103 to a sensing position above a sensing surface; a second process of moving the nozzle 103 downward until an interval between a bottom end of the nozzle 103 and the sensing surface 107 a becomes equal to a predetermined sensing distance L and moving the nozzle 103 upward upon the interval reaching the predetermined sensing distance L; and a third process of detecting a pool at the bottom end of the nozzle 103 by a sensing device 104 sensing whether a liquid material adheres to the sensing surface 107 a . Also provided is a detection device that executes the same method.

Inventors

Kazumasa Ikushima

Assignees

MUSASHI ENGINEERING, INC

Dates

Publication Date: 20260507
Application Date: 20250218
Priority Date: 20240222

Claims (20)

1 . A nozzle bottom pool detection method for detecting a pool at a bottom end of a nozzle of a liquid material discharge device, the nozzle bottom pool detection method comprising: a first process of moving the nozzle to a sensing position above a sensing surface; a second process of moving the nozzle downward until an interval between the bottom end of the nozzle and the sensing surface becomes equal to a predetermined sensing distance and moving the nozzle upward upon the interval reaching the predetermined sensing distance; and a third process of detecting a pool at the bottom end of the nozzle by a sensing device sensing whether a liquid material adheres to the sensing surface.
2 . The nozzle bottom pool detection method according to claim 1 , wherein the liquid material is not discharged from the nozzle during execution of the second process.
3 . The nozzle bottom pool detection method according to claim 1 , wherein the nozzle is a nozzle having one discharge port at the bottom end.
4 . The nozzle bottom pool detection method according to claim 1 , wherein the nozzle is a nozzle having a cylindrical or tapered shape.
5 . The nozzle bottom pool detection method according to claim 1 , wherein the sensing device is any of an image capturing device, a laser displacement meter, and an ultrasonic sensor.
6 . The nozzle bottom pool detection method according to claim 1 , wherein the sensing surface is any of an upper surface of a plate-like member for sensing, an upper surface of a tape-like member, and an unused area of an upper surface of a workpiece.
7 . The nozzle bottom pool detection method according to claim 1 , wherein the predetermined sensing distance is set within a range of ½ to 2 times an outer diameter of the bottom end of the nozzle, or ⅓ to 7 times a diameter of a discharge port of the nozzle.
8 . A liquid material application method comprising: an application process of discharging a liquid material from the nozzle to a workpiece; and a pool detection process of executing the nozzle bottom pool detection method according to claim 1 before or after executing the application process.
9 . The liquid material application method according to claim 8 , further comprising a process of cleaning the bottom end of the nozzle when it has been detected in the pool detection process that the liquid material adheres to the sensing surface.
10 . The liquid material application method according to claim 9 , comprising a post-cleaning application process of discharging the liquid material from the nozzle to the workpiece after executing the cleaning.
11 . The liquid material application method according to claim 8 , further comprising, when a pool of which volume is not acceptable has been detected at the bottom end of the nozzle in the pool detection process, issuing an alert that can be visually or aurally recognized or transmitting a command signal to notify an external device of abnormality, and stopping execution of the application process.
12 . The liquid material application method according to claim 8 , further comprising: an importing process of importing the workpiece to an application position, the importing process being performed before the application process; and an exporting process of exporting the workpiece from the application position, the exporting process being performed after the application process, wherein the pool detection process is executed concurrently with any of the importing process and the exporting process.
13 . A nozzle bottom pool detection device comprising: a moving device configured to move a discharge device having a nozzle above a sensing surface; a sensing device configured to sense a liquid material having adhered to the sensing surface; and a sensing control device configured to control operation of the moving device and the sensing device, wherein the sensing control device is configured to execute: a first step of causing the moving device to move the nozzle above the sensing surface; a second step of causing the nozzle to move downward until an interval between a bottom end of the nozzle and the sensing surface becomes equal to a predetermined sensing distance and move upward upon the interval reaching the predetermined sensing distance; and a third step of causing the sensing device to sense whether the liquid material adheres to the sensing surface thereby detecting a pool at the bottom end of the nozzle.
14 . The nozzle bottom pool detection device according to claim 13 , wherein the sensing control device includes a function of setting the predetermined sensing distance.
15 . The nozzle bottom pool detection device according to claim 13 , wherein the moving device is capable of moving the sensing device above the sensing surface.
16 . An application apparatus comprising: the nozzle bottom pool detection device according to claim 13 ; a discharge device having a nozzle; a worktable configured to hold a workpiece; a base on which the worktable is disposed; a transport device configured to transport the workpiece to the worktable; and an application control device configured to control operation of the discharge device and the moving device, wherein the application apparatus performs application on the workpiece while causing the moving device to move the discharge device and the workpiece relative to each other based on a relative movement command from the application control device.
17 . The application apparatus according to claim 16 , further comprising, on the base, a cleaning device configured to clean the bottom end of the nozzle, wherein the sensing control device is configured to execute a fourth step of causing the cleaning device to clean the bottom end of the nozzle when it has been detected in the third step that the liquid material adheres to the sensing surface.
18 . The application apparatus according to claim 16 , further comprising a notification device configured to issue an alert that can be visually or aurally recognized, wherein the sensing control device is configured to execute a fourth step of causing the notification device to issue the alert when it has been detected in the third step that the liquid material adheres to the sensing surface.
19 . The application apparatus according to claim 16 , wherein the sensing control device includes a function of setting a timing-related condition for executing the first to third steps.
20 . The application apparatus according to claim 16 , wherein the discharge device is a flying-discharge type dispenser configured to discharge and fly a droplet from a discharge port of the nozzle.

Description

TECHNICAL FIELD The present invention relates to a method and device for detecting whether there is a pool of liquid material at a bottom end of a nozzle in a liquid material application apparatus. BACKGROUND ART In a process of manufacturing electronic components or the like, a discharge device is used for application of liquid material. For example, a dispenser is used in a process of applying a liquid resin to a semiconductor element mounted on a board. When the dispenser performs successive application on workpieces, a pool of the liquid may occur at a nozzle tip, which affects application accuracy. Particularly, a flying-discharge type dispenser, which is recently becoming more common, is affected by the liquid pooling at a nozzle tip, and sometimes suffers from troubles such as the liquid not separating from the nozzle to fly, an excessively large or small amount of flying liquid, and the liquid not flying along the central axis of the nozzle. Conventionally, a pool at a nozzle tip has been dealt with using a method in which a camera for monitoring a nozzle tip from a lateral side is provided to sense abnormality of the nozzle tip in an image (Patent Document 1), a method in which trial application is performed on a plate that is not an application target and is monitored by a camera to determine whether or not an application amount is appropriate (Patent Document 2), or the like. PRIOR ART LIST Patent Document Patent Document 1: Japanese Patent Laid-Open Publication No. 2014-236136 Patent Document 2: Japanese Patent Laid-Open Publication No. H4-334568 SUMMARY OF THE INVENTION Problems to be Solved by the Invention However, the method of capturing an image of a nozzle tip to determine whether a pool is within an acceptable range has an issue that, when a pool occurs at a bottom end of the nozzle, it is difficult to determine whether the volume exceeds the acceptable range. In addition, the method of capturing an image of a nozzle tip to determine whether a liquid pool is within an acceptable range has an issue that it is necessary to secure an installation location of a camera that captures the nozzle tip from a lateral side and to set up an optical system for monitoring. On the other hand, the method of performing trial application to determine whether it is appropriate or not has an issue that a normal application result differs little from an abnormal application result and it is difficult to determine whether the volume of a pool at the bottom end of the nozzle exceeds the acceptable range. An object of the present invention is to provide a technology that enables easy and highly-accurate determination on a pool that has occurred at a bottom end of a nozzle. Means for Solving the Problems In a flying-discharge type dispenser, when discharge is successively performed, a liquid pool emerges at a nozzle tip (especially bottom surface), and may gradually spread all over the tip. FIG. 8 is a schematic diagram for explaining how a pool emerges and develops at a nozzle tip, where (A) illustrates lateral views of a nozzle 801, and (B) illustrates bottom views of the nozzle 801. The nozzle 801 has a cylindrical shape and includes, at its end, a hole portion 802 from which a liquid material 804 is discharged, and a wall portion 803 surrounding the hole portion 802. Soon after a pool of the liquid 804 emerges, it spreads to a dimension roughly equal to the diameter of the hole portion 802 (FIG. 8 (1)). When discharge is successively performed and the volume of the pool of the liquid 804 increases, the pool begins to spread beyond the hole portion 802 to the wall portion 803 (FIG. 8 (2)). When discharge is further successively performed and the volume of the pool of the liquid 804 has increased, the pool spreads all over the wall portion 803 to reach the outer periphery (FIG. 8 (3)). The inventor has gained the following insight while conducting research and has conceived the present invention based on the insight. FIG. 7 is a schematic diagram for explaining a method of sensing a pool through trial application, where (A) illustrates lateral views of a nozzle 701 and an application surface 702, and (B) illustrates top views of the application surface 702. In FIG. 7, (1) illustrates a state of a pool 703 immediately after it emerges, (2) illustrates a state of the pool 703 beginning to develop, and (3) illustrates a state of the pool 703 covering a large part of the nozzle 701. In the method by trial application illustrated in FIG. 7, determination on a pool is performed, for example, depending on the diameter of the liquid material 703 applied to the application surface 702 as a result of executing the trial application. In the method by trial application, an application result when the pool has developed (diameter D3) greatly differs from an application result when the pool begins to develop (diameter D2), allowing for easy determination. However, the application result when the pool begins to develop (diame