Two-Station Projection Welding Machine for Automotive Shock Absorber Locating Plates

Shock Absorber Locating Plate Welding Cell: Two Stations, Two Seconds Of Weld, Six Seconds A Part

Application story  ·  Projection welding of locating plates onto shock absorber brackets, delivered to an automotive plant and running in volume production

The part is small: a stamped locating plate with weld projections, a few millimetres of it to be welded onto the bracket and bush of a shock absorber. Left and right hand parts are mirror images of each other. Everything that makes this joint difficult - the size of the plate, the angle it has to sit at, the projections that have to collapse at the same moment - is decided before the current is switched on, by the fixture.

The cell as built: aluminium frame with transparent doors, press head and cylinder on top, control cabinet and HMI on the right, stack light above

A Small Plate, A Tight Position

A shock absorber bracket is welded in left and right pairs. The locating plate has to sit at a set angle and a set left-right position, because the next assembly station picks up on it. When an operator places the plate by hand, that angle moves: the plate slides while the clamp comes down, the bracket is not quite flat on its seat, and the weld ends up a fraction of a millimetre out. On a safety part that fraction is the difference between a bracket that bolts up and one that has to be reworked.

Welded by hand, the same part also suffers from the projections themselves: projection welding needs the force and the energy to match the number and height of the projections. With a general-purpose press the force wanders, the projections collapse unevenly, and the batch ends up with collapsed points, spatter and weld nuggets of different sizes.

Typical part: the shock absorber body with its bracket; the small locating plate is welded onto the bracket by projection welding

Three Locating Features Close Before The Current Does

The fixture is where this cell earns its keep. It closes on the part in a fixed order and takes the position away from the operator:

· Limit 1 holds the parallelism of the shock absorber body - the bracket cannot tilt on its seat

· Limit 2 controls the angle and the left-right position of the locating plate

· The lower electrode is profiled to the plate, so the plate cannot rotate or slide sideways once it is seated

· A locating cylinder pushes the plate home before the weld cylinder comes down, which removes the gap left by hand placement

Two identical stations are built into one frame. Each has its own fixture and its own weld head, so the cell can run one station on a small order or both at once when the line is busy - without changing anything over.

Two stations under one frame: each with its own fixture, press head and two-hand start, the load area closed by a light curtain on each side

Output That Does Not Move Between Parts

The weld is made by a Pudian medium-frequency transformer and a dedicated weld controller: several projections are welded in one discharge, with the pressure and the current held where they were set. The schedule is matched to the bracket, so the projections collapse together and the plate ends up at the same height on every part.

Water runs through the electrode holders and the electrode tips. On a copper electrode that sees a weld every few seconds, the cooling is what keeps the tip from picking up zinc and copper and mushrooming - the face stays the shape the schedule was set for, the current path does not drift, and the tip lasts through the shift instead of being dressed twice a day.

Six Seconds A Part, Loaded By Hand

The cell is semi-automatic: the operator loads, the cell does everything else. The sequence is fixed, and the machine will not start the weld until each step has completed:

01   Operator places the locating plate and the shock absorber body in the fixture

02   Both start buttons pressed - the two-hand start keeps the hands out of the cell

03   Locating cylinder pushes the plate home

04   Upper clamp cylinder closes and applies the weld force

05   Welder discharges - about 2 seconds at the set schedule

06   Cylinders return to the open position

07   Operator unloads the finished part

Weld time is around 2 seconds and the complete part cycle around 6 seconds, which is what makes hand loading viable at volume. The load opening is covered by a safety light curtain, the frame is closed on three sides, and the two-hand start means a weld cannot be triggered with a hand inside the cell.

Front of the cell: load opening with light curtain bars, two-hand start buttons on both sides of the fixture, HMI on the swing arm

Delivered As A Working Cell, Not A Machine

The scope of supply is the whole cell: frame, custom fixture, air and water circuits, welding control, safety light curtain and a common base - assembled, wired and tested before it leaves the works. Assembly, burn-in and a weld trial on the customer's own parts are done in-house, so the machine that arrives has already welded the customer's bracket.

Lead time is 40 working days. Our engineer installs and commissions the cell on site, trains the operators and runs the first production shift with them, so the line switches over without a trial-and-error period.

Key Specifications

Where It Welds

· Shock absorber brackets and locating plates, left and right hand parts

· Damper and strut sub-assemblies with projection-welded plates

· Bush and sleeve assemblies with a stamped reinforcement plate

· Chassis and suspension brackets carrying small stamped plates

· Other small-plate-on-bracket projection welds in automotive parts

Fixtures and electrodes are built from the customer's part drawing or sample, and the weld schedule is set on real parts before the cell is released.

How A Custom Cell Is Built

01   Part drawing and weld process review

02   Weld trial on our own press

03   Process proposal and quotation

04   Fixture, electrode and guard design in 3D

05   Manufacturing and in-house assembly

06   Burn-in test and weld trial before shipment

07   Delivery and on-site installation

08   Operator training and pre-production run

09   After-sales service and spare electrodes

Talk to Pudian Technology

Guangdong Pudian Automation Technology Co., Ltd designs and builds custom resistance welding cells in-house: fixtures, electrodes, air and water circuits, weld control and guarding - one team, one solution. Send us the part, the projections and the cycle time you need, and we will run a weld trial and send the sections back.