Pictured below is a 12VDC dual pulse spot welder timer controller which we were recently commissioned to build.
Spot welding (resistance spot welding – RSW) is used to join metal surfaces by passing a large electric current through them. Because of the heat generated by the resistance to the electric current, the contacting metals melt together forming a weld at the spot through which the current is passing.
In order to get good clean reliable welds and not to burn holes through the metal, it is essential that the pulse of electric current is of a suitable duration which depends on the types and thicknesses of the metals to be welded as well as many other factors. Therefore an accurate timer controller is required for consistent welds.
For the best spot welds, a dual pulse controller is used in which the electric current flows for a time (pre-weld), then there is a brief pause, and then electric current flows again (welding). The first pulse clears away any plating or surface oxidation, and then the second pulse welds the now clean base materials together. Using a dual pulse welder also reduces spitting.
REUK Dual Pulse Spot Welder Controller
Our controller offers two modes of operation: single pulse mode and dual/double pulse mode. Pictured below is a view of the built in OLED display when in dual pulse mode.
The user can set the durations of Pulse 1, the pause time, and Pulse 2 in 0.01 second steps between 0.01 and 1.99 seconds (0.99 seconds for units supplied before 10th July 2018).
In single pulse mode, the duration of just one pulse has to be set by the user. (A future update of this device will include up to 10 user-programmable presets for increased convenience.)
On board buttons are provided for toggling between the single and double pulse modes, entering programming mode to set the timings, and making a spot weld with the displayed settings. Screw in terminals are provided so that external buttons can be connected – for example a foot pedal to make a weld with your hands free.
This version of the welder controller is fitted with a 10A relay which is used to power a 5A rated solenoid which in turn controls the welder. We can also make these controllers with a 12V 1A output for connection to an external relay solid state or otherwise, or a small relay for connection in parallel with the on/off button of the welder.
Buy a Welder Timer Controller
If you need any type of welder timer controller, please email email@example.com with details of any special requirements. The controller as described above is available at £21.95 plus postage.
Dual Pulse Spot Welder Timer Instructions
There are two buttons on the controller. If you press the ‘down’ button, you can toggle between single pulse and dual/double pulse operation. The display will change to show which mode you are in: SINGLE or DBL (double) as well as showing the durations currently programmed into the device.
If you press and hold the down button for more than one second, the display will show SET TIMERS. If you are in single pulse mode, you can now set the single pulse duration. If you are in double pulse mode you can now set the durations of pulse 1, the pause time, and pulse 2. The top line of the display will show what is currently being programmed (Time 1, Pause Time, or Time 2), and the bottom line will show the current value. Use the up and down buttons to increase or decrease the displayed value (within the range 0.01s to 0.99s). Five seconds after you last touched a button, the top line of the display will show -SAVED- and the value will be saved in long term memory (still available the next time you power on the controller). If you are in double pulse mode, you will now be asked to set the pause time and the duration of the second pulse in exactly the same way that Time 1 was set. (When using the up and down buttons to increase or decrease a time value, you can press and hold the button to move faster through the numbers.)
If you press the up button, the controller will run. The relay will close for the duration of Time 1 and then open again. If you are in double pulse mode, it will then remain open for the duration of Pause Time and then close for the duration of Time 2.
In addition to the buttons on the controller board itself, screw in terminals are provided to which you can connect external buttons of your choosing – e.g. a foot pedal operated button, or a larger hand operated button etc for your own convenience.