ENGINEERING SERVICES AND CONSULTING Srl

Special automatic machines: dot matrix impact printheads manufacturing.

Once the printhead was designed, we were involved in the design and construction of the special machines needed for mass production.

Automatic selection machine.

Among the components that are part of the printhead (about 35 different codes) the one with the highest technology is the armature (in our case 24 per head): it is made of cobalt steel and after being punched and coined (with a die made by our partner) it must be 100% tested. In order to do this, we have developed a special automatic machine that verifies different parameters (thickness, flatness,...) and selects the good armatures from the waste ones.

Laser brazing machine.

The armatures must then be joined to the needles (diameter 0.2-0.25 mm) by brazing. This operation is carried out by a special automatic machine: a laser brazing machine which, after having positioned the needle and armature in a precise position, deposits the brazing paste which is then melted using a laser beam.
This is a critical operation that is constantly monitored by means of two cameras.

Once this group has been completed, the entire printhead is assembled using a series of standard machines (tangential grinding, washing machines, ovens, etc.) until the complete head is obtained.

Special grinding machine.

Once the assembly has been completed, the needles protruding from the printhead guide should be ground to ensure their flatness and height of protrusion.

For this operation, a special grinding machine is used that flattens the needles at a predefined height and carries out a brushing operation to eliminate dust and grinding waste from the end of the needles.

Parametric test equipment.

After the needle grinding operation the printhead can be considered as finished, it is now necessary to measure the key parameters (needle stroke, impact force, coil resistance, etc.) to check that they correspond to the design parameters.

For this operation we have designed and built a parametric test equipment that measures, collects and stores the values of these key parameters in a database.

Only after the printhead has passed this test can it start the preliminary running-in step and then be installed on the printer.

Shipment.

The machines described above (some in 2 units) were shipped to China where they were installed in a specific workshop for the production of the heads we designed.