Pedal Spot Brazing Machine

INSTALLATION PROCEDURE

Machine Erection / Placement

• It is always advisable for the installer or client to erect the machine on solid ground.

It can be done by either of the two methods:

By the use of nut & bolt:

Slab base of 3" height and length x width of base matching machine dimensions. The bolt should be cemented on plain base P.C.C. with bolt protruding above ground till 2"-2". Machine base should be fastened by two nuts, in order to force the machine towards the ground for retaining shocks/vibrations.

By welding:

• The machine can also be bolted on welded plate on an M.S. platten directly.
• Dimensions suitable for the platten base should be suitable to machine geometry and ¾” to 1” (thickness)
• However machine can also be placed on its legs as it is and can be started right away

Customer’s Scope

• Things that would be required for the installation by the client:
• A cooling tower for maintaining 25-30deg C.
• 63A switch fuse unit (3 phase)
• 7/16. copper cable - 2mtrs each for L1 & L2.

Electrical connection – SWITCH FUSE UNIT

Open the 63 Amp switch fuse unit and connect the R & Y (L1 & L2) phases to the 63 Amp connector of the Micro Processor control. Fig. below shows 63 A switch fuse unit.

MICRO PROCESSOR CONTROL

Open the rear panel of the machine control and you will find the thyristor and 63 AMP 4 way connector. The diagram below shows the connections as mentioned above connect the L1 and L2 from the switch fuse unit to the L1 & L2 of the micro processor control as shown below. Please use 7/16 type electric wire

Water connection

The inlet and outlet nozzle is at the side panel of the machine with the water entry nozzle on the left & water exit nozzle on the right.

Connect suitable 3/8"  hose pipe from cooling tower to machine inlet and machine outlet back to the cooling tower.

POINTS TO CHECK BEFORE STARTING

• Check whether electrical connections are proper and whether 440V A.C. voltage is is available at the 63 A connectors of the pedal brazing machine
• Check the flow of water as: water into machine -> water out of machine -> water into cooling tower.
• Read the operational manual once again before starting.

FUNDAMENTALS OF RESISTANCE BRAZING TO REMEMBER BEFORE STARTING

Now, before we actually start the brazing process, we must know the brazing sequence which is

Squeeze > Braze > Hold > Off

(Current Percentage parameter set will work during braze on time)

Lets read every sequence in detail

Squeeze time

Squeeze time is the time during the electrodes downward travel, before brazing process can take place. Time is in cycles (0-100). Lower the cycle time in squeeze, the lesser the waiting period before brazing, and higher the cycle time in squeeze more the delay in brazing or delay before brazing

For eg. 1 sec = 50 cycles. Now if you enter 25 cycles of squeeze time, then the time gap between start of cylinder movement and braze current cycle to pass is 0.5 secs

Braze Time

Here the braze time period is determined by its on time, which means current passes through the job during the braze time in seconds from 0- 100 (secs). The braze time is useful in auto mode i.e. repeat. In the case of manual mode or single mode, the brazing time depends on the amount of time the operator keeps the pedal or the limit switch pressed.

Auto mode eg. If the data for braze time entered is 12 seconds, it means current passes for 12 seconds through the job and automatically the current flow stops after 12 seconds

Current Percentage

Current percentage is unlike cycle time where current shows its intensity of energy (H=I^2RT), which can be increased and decreased when we require it to. Heavy jobs require heavy currents hence percentages need to be varied as per job thickness. 0 – 100 % is the maximum heat deliverance / throw. 50% power means ½ the utilization of power source (i.e. the transformer). Desired current percentage of brazing are just about 40 - 60%. or may be a bit more.

Hold Time

The time for which the electrodes stay held in pressed condition with each other without passing current is hold time. In brazing its not applicable, since hold time thoroughly depends on the operators will.

Off time

Time between end of operation and start of operation is known as Off time which is not at all applicable for brazing but highly recommended for spot welding machine.

Now that we are familiar with squeeze, braze , hold and off time, lets understand the programming part in the micro controller. (Refer the STARTING THE MACHINE PAGE)