Hello, dear readers and homemade products!
As you know, a conventional welding machine is not suitable for connecting thin metal elements to each other. Especially when it comes to sheet metal, non-ferrous metals. In this case, a spot welder is used, which allows you to almost instantly heat up a small area and weld two parts together.
The spot welding process is one of the oldest welding methods in which two or more metal sheets are welded together without using any filler material.
This is very convenient when assembling various cases, such as computer ones, and other metal structures.
In this article, the author of the YouTube channel “Mistry MakeTool” will tell you how to make a machine for spot welding.
This project is quite simple, and can be repeated in a home workshop.
Materials necessary for homemade.
– Microwave oven transformer
– Controller for a spot welder
– Fan GDStime AC 220
– Pushbutton switch for angle grinders
– 220 switch with connector
– Wire terminals, brass bolts, nuts
– Heat shrink tubing with glue filler
– Welding wire 50 mm² 1.5 m, aluminum angle, sheet
– Sheet plywood (18 mm), wooden beams, carpentry glue, spray paint, sandpaper
– A set of screws, wood screws, nails.
Tools used by the author.
– Drills for metal
– Hand circular saw or electric jigsaw
– Geyfer grip – Svenson's square, hammer, file
– Clamps, hacksaw for metal, universal knife – Screwdriver with a set of bits, wrenches.
So, the heart of this device will be such a transformer from a microwave oven.
First of all, you need to bite off the excess wires of the secondary winding, and cut off part of it with a hacksaw.
The remnants of the winding are carefully knocked out. It is imperative not to snag the primary winding or damage its insulation.
The replacement of the secondary winding will be a 50 mm² welding wire with a length of about 1.5 m.
This wire does not go through the holes, and the foreman had to remove the first layer of insulation.
Now one and a half turns are formed secondary winding.
Excess wire is cut off, and the insulation is removed at the ends.
wire clamps are put on the stripped ends and crimped using geyfer grip .
The terminals are additionally protected with a glue-filled heat shrink tubing . This is necessary not for insulation, but so that the wire does not get tattered.
The assembled device is worth testing. The author connects the power wire, and closes the terminals of the secondary winding with a nail. After switching on, a few seconds pass, and the nail simply melts, having worked a little in the form of an incandescent light bulb.
Most likely like this the device will work for a long time, and it is desirable to cool the transformer. The master cut out a plywood base, and fixes on it a 220V fan .
a lining that is glued to the base and fixed with studs.
From the remainder of the stripped insulation the master cuts the linings and inserts them under the transformer mounts. The transformer is screwed to the base with four self-tapping screws.
Another bar is attached along the base to increase rigidity. She, like the rest of the parts, is cut from 18 mm plywood.
To make the supports, the master had to glue two square plates together.
The resulting workpiece is cut into two identical trapezoidal supports.
Having put the supports on the base, the author tries on a block to them (this will be a pressure lever). To eliminate the gap between the supports and the bar, a couple of pads had to be glued to them.
Now you can fix the cable on the base with a pair of brackets.
Next, holes are drilled in the supports and the bar for axle, retainer and spring stop.
The hinged arm mount is assembled and screwed to the base.
The device will be turned on on the 220V line, for which the author uses a push-button switch from the grinder .
A seat in the lever is formed for it.
For such devices it is better to use copper electrodes, but a brass pin is also suitable. The author sharpens the ends of the electrodes under the cone.
To protect the wood of the base from charring, the master made a lining of aluminum sheet.
The electrodes are tightened with two nuts on the terminals.
Now you can install the spring stopper, the spring itself, and then the pressure lever.
< a href = "https://usamodelkina.ru/uploads/posts/2021-06/1624839953_spw-261.jpg" rel = "prettyPhoto"> Before fixing the upper electrode , the author brings their ends together, and fixes the upper cable with clamps. Only after that the clamp is stuck to the lever.
Two overlays are glued to the sides of the start button.
Almost all the details are ready, you need to bend the protective cover out of a metal sheet.
< img class = "aligncenter" alt = "Making a spot welding machine" src = "https://usamodelkina.ru/uploads/posts/2021-06/1624839957_spw-307.jpg"/> The cover is drilled with vents, seats for a power indicator, and a power button. A handle is attached to the upper part.
The electrical circuit is very simple, and almost everyone will assemble it.
Holes are drilled in the lever, two wires are passed through them, and connected to the start button.
< a href = "https://usamodelkina.ru/uploads/posts/2021-06/1624839960_spw-340.jpg" rel = "prettyPhoto"> Now the wires are being laid , it is desirable to fix them with brackets or ties.
To the metal case of the transformer the ground wire must be connected.
It remains to put the indicator and the power button in place.
Instead of such a button, you can install a switch with a connector .
A little later, after a series of tests, the author decided to paint it. As a result, the device looks beautiful and finished.
Everything is ready, you can start welding.
To join parts using the spot welding process, they must be precisely aligned, since it is not easy to correct the position after welding.
The welding process involves an application pressure in the welding zone using electrodes that pass an electric current through the workpieces to be welded. The workpiece material melts, after which the current is turned off, the pressure from the electrodes remains for some time, and the molten metal solidifies, forming a weld joint.
For spot welding, copper alloy electrodes are best suited, which can withstand high temperatures and pressures. If the electrodes and parts are positioned correctly, a current is turned on that flows from one electrode to the other with a very high force. The consumable heats up so much that it melts, and thus both workpieces are connected.
Due to its lower thermal conductivity and higher electrical resistance, the steel material is relatively easy to spot weld, with steel with a low carbon content being the most suitable for this. However, steels with a high carbon content are prone to fracture in welds as they tend to form hard and brittle microstructures.
In this process, the time during which the electric current must pass through the workpieces varies depending on the material of the workpieces. To automatically control the optimal welding time, it is best to equip this machine with a dedicated controller for a spot welder .
If you do not need such a powerful device, and the main tasks are soldering tapes to batteries, then you can take such a ready-made mini-machine for spot welding Bifrc DH20 .
I thank the author for a master class on making a spot welding machine.
Good mood, good health, and interesting ideas to everyone!
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Hello, dear readers and homemade products!