Products From Which A Few Aspects Of Membrane Switch Is Analysed To Determine Whether Qualified
- Sep 01, 2017 -
Membrane switch, the circuit, insulation panels, isolation layer and the lower four some part circuit.For light touch type is normally open to switch, under normal circumstances the two membrane switch contact is disconnected, when has the external force on membrane switch touch, instantaneous through two normally open contacts, not force, switch contact rehabilitation normally open state, usually on the circuit contact the drum or add pot (feel), press the membrane switch, circuit on contact deformation down, and the touch pad of the circuit under conduction, fingers, contact bounce back on the circuit, circuit disconnect, loop triggers a signal, so the following together to understand membrane switch system from which a few respects to check:
Membrane switch is really qualified to check the products from the following aspects:
(1) of the material: substrate, silver paste, carbon ink, spacers, adhesives, glue, reinforcement plate, insulation print should fit the drawing rule.
(2) shape: shape, conductor lines, insulation disposal, such as plate combination should fit the drawing rules or supply samples of things.
Mechanical properties (6) : stamping burrs and die extrusion bending dimensions: stamping burrs and crowded curved scale, should not be greater than 0.2 mm, and no conductor bearing should be toward the side, top and bottom line azimuth migration: line up and down the switch contacts between azimuth offset each other promise for public service Ф 0.5 mm..
(3) combination of appearance: state: appearance can not have residual data chip, foreign bodies, stain, high and low and attached to the appearance and the grease, fingerprints, on a line inside the coining of burr shape.Scar: all lines and contact shall not be cut through table (that is, the cut on the line cut to base material).Minor scratches and does not affect the impedance for the principle.Carbon ink appearance is easy to scratch, scratch to does not affect the circuit conduction for the principle.Foreign bodies: line should be attached to any foreign body.
(4) line conductor department: the thickness of the conductor: usually conductor thickness control in 7-12 microns, and should be uniform, lubrication.Conductor deformity and pinhole: according to the following chart specifications concluded that within each of the 50 mm promised a.Carbon ink: hide on the silver pulp line carbon ink, should guarantee the complete silver paste mask, its thickness 8 to 10 microns, can not have extremely significant silver pulp bulge.Break, short circuit, do not allow any conductor broken, short circuit.
(5) insulation printing: all membrane switch touch point can not have any ink adhesion, insulation insulation ink surface should be smooth, prevent any air bubbles or pinhole defect and influence of insulation effect.After adhesion strength: insulation dry ink, the ink surface abutting again after 24 hours, the weight of each other to ensure insulation does not stick to each other.No bubble with a pressure sensitive adhesive tape attached with a hand pressure after 1 minute, agile, also can not have ink drops.Jump line: all jump line department according to the circuit conductor requirements, and all the jumper wire products needs to open the door by 100%, the short circuit test and insulation resistance test.Make sure no any open, short circuit and insulation resistance should be greater than 500 m Ω vdc1 (500 minutes).