Method of controlling contact load in electronic component mounting apparatus

Abstract

A method of controlling contact load in an apparatus for mounting electronic components on a substrate includes a head holding an electronic component being lowered at a first speed to a first position where the electronic component does not contact the substrate. The head is lowered at a second speed slower than the first speed from the first position until a predetermined target contact load is detected. The head is moved down by a small step for a predetermined distance at the second speed and a contact load is measured after moving the head down. The method includes determining whether a measured contact load has reached the predetermined target contact load. The moving and the measuring is sequentially repeated until the measured contact load reaches the predetermined target contact load. The predetermined distance is set to a first predetermined distance when moving the head down until the electronic component contacts the substrate. The predetermined distance is set to a second predetermined distance when moving the head down after the electronic component contacts the substrate and the second predetermined distance is smaller than the first predetermined distance.

1 . A method of controlling contact load in an apparatus for mounting electronic components on a substrate, in which a head holding an electronic component is lowered at a first speed to a first position where the electronic component does not contact the substrate, the head being lowered at a second speed slower than the first speed from the first position until a predetermined target contact load is detected, the method comprising:
 moving the head down by a small step for a predetermined distance at the second speed;   measuring a contact load after moving the head down; and   determining whether a measured contact load has reached the predetermined target contact load, the moving and the measuring being sequentially repeated until the measured contact load reaches the predetermined target contact load,   wherein the predetermined distance is set to a first predetermined distance when moving the head down until the electronic component contacts the substrate,   wherein the predetermined distance is set to a second predetermined distance when moving the head down after the electronic component contacts the substrate, and   wherein the second predetermined distance is smaller than the first predetermined distance.   
   
   
       2 . The method according to  claim 1 , further comprising:
 halting the head for a predetermined period of time after moving the head down and before measuring the contact load.   
   
   
       3 . The method according to  claim 1 ,
 wherein the second predetermined distance is adjustably set in accordance with the predetermined target contact load.   
   
   
       4 . The method according to  claim 1 ,
 wherein the predetermined distance is set to a first predetermined distance when the measured contact load is zero,   wherein the predetermined distance is set to a second predetermined distance when the measured contact load exceeds zero, and   wherein the second predetermined distance is less than the first predetermined distance.   
   
   
       5 . The method according to  claim 4 ,
 wherein the second predetermined distance is adjustably set in accordance with a difference between the measured contact load and the predetermined target contact load.   
   
   
       6 . The method according to  claim 1 ,
 wherein the measuring of the contact load is repeated until a different contact load is measured when the measured contact load exceeds zero and the measured contact load is the same as a previously measured contact load.   
   
   
       7 . The method according to  claim 1 ,
 wherein the second predetermined distance is adjustably set such that the movement and the measurement is sequentially repeated until the measured contact load reaches the predetermined target contact load.   
   
   
       8 . The method according to  claim 1 ,
 wherein the predetermined distance is adjustably set within a range of 0.2 um to several um.   
   
   
       9 . A method of controlling contact load in an apparatus for mounting electronic components on a substrate, in which a head holding an electronic component is lowered at a first speed, to a first position where the electronic component does not contact the substrate, the head being lowered at a second speed slower than the first speed from the first position until a predetermined target contact load is detected, the method comprising:
 moving the head down by a small step for a predetermined distance at the second speed from the first position until the electronic component contacts the substrate;   measuring contact load, while the head is not moving down, after moving the head down by a predetermined distance; and   determining whether the measured contact load has reached the target contact load, the moving and the measuring being sequentially repeated, while the head is not moving down, until the measured contact load reaches the predetermined target contact load.   
   
   
       10 . The method according to  claim 9 ,
 wherein the predetermined distance is set to a first predetermined distance when moving the head down until the electronic component contacts the substrate,   wherein the predetermined distance is set to a second predetermined distance when moving the head down after the electronic component contacts the substrate, and   wherein the second predetermined distance is smaller than the first predetermined distance.   
   
   
       11 . The method according to  claim 9 ,
 wherein the predetermined distance is set to a first predetermined distance when moving the head down until the electronic component contacts the substrate,   wherein the predetermined distance is set to a second predetermined distance when moving the head down after the electronic component contacts the substrate, and   wherein the second predetermined distance is adjustably set in accordance with a difference between the measured contact load and the predetermined target contact load.