Digital Squeeze Monitor (DSM)

The Digital Squeeze Monitor has been developed to enable the correct welding forces
to be set for resistance welding guns ( resistance spot welders ).
The instrument also enables the correct timing of the resistance welding cycle to be set.

· Enables optimum settings for resistance welding guns
· Reduces the number of defective resistance welds
· Maximises production rates
· Ensures consistent weld quality

Specification

Function	Used to measure the squeeze force and peak force between resistance welding electrodes.
Squeeze Force	This is defined as the compressive force between the electrode tips at the instant an electrical potential difference greater that 1 volt AC is applied to the electrodes. The maximum voltage applied by the electrodes will by 24 VAC. When welding is carried out, this is the force which occurs between the electrode tips at the time the welding current is applied
Peak force	This is defined as the maximum compressive force produced by the electrodes during the welding cycle
Force Range	0 - 1000 Kg Metric, or 0 - 1999 lbs force Imperial
Accuracy	+/- 1Kg +/- 1% for Metric Units +/- 2½ Lbs force +/- 1% for Imperial Units
Diameter of welding electrode	Between 6 and 20 mm diameter, Or between 0.24 and 0.80 inches
Minimum Electrode Gap	10mm 0.4 inches
Power Supply	4 AA cells

Operation

1. Switch on - press the single button on top of the housing. The display will read zero.

2. Place the load cell on one of the welding gun electrodes. Ensure that when the welding gun is operated, the second electrode will strike the other side of the load cell.

3. Activate the gun so that it attempts to make a weld on the load cell. The squeeze force and the weld force will be shown on the displays.

4. Press the button to zero the display so that a new measurement can be taken if required.

5. The force on the welding gun should be adjusted so that the peak force is correctly set.

6. To set the correct Squeeze time, adjust the timer on the gun so that the Squeeze force is not more than 10kg(20lb) lower than the peak force. If the Squeeze force is more than 10kg(20lb) lower than the peak force, then the welding current is starting too soon and the squeeze time should be increased.

7. If the Squeeze force is the same as the Peak force, then the Squeeze time is unnecessarily long and it can be shortened until the Squeeze force is up to 10kg(20lbs) lower than the peak force.

Batteries

The battery compartment is located at the opposite end of the unit from the load cell.

Safety Notes

The DFM uses 4 AA cells and is therefore an electrically safe instrument. It does not generate any high frequency signals and will not interfere with radio transmitters and receivers. The AA cells are not rechargeable and should be disposed of safely when they have become discharged.

In operation, the DFM is held by hand between the electrodes of a resistance welding gun.. The handle and display region of the instrument is insulated from the force sensor. When measurements are made, the resistance welding gun is made to attempt a weld on the force sensor of the DFM. Care should be taken to ensure that no part of the hand is positioned so that it can come into contact with the resistance welding electrode