Pcb proofing, small and medium batch production
A Buffer Block, stop, bumper, bumping post, bumper block or stop block (US), is a device to prevent railway vehicles from going past the end of a physical section of track.
PCB circuit board production process
Cutting - inner layer graphics - lamination - drilling - electroplating - outer layer - solder mask - surface treatment - forming - electrical testing - FQC - FQA - packaging - finished product
plating
Copper sinking (principle)
The drilled PCB board is chemically treated to deposit (cover) a uniform, heat-resistant metal copper in the drilled hole.
Production process:
Grinding plate - conditioning agent - washing - micro-etching - washing - pre-dipping - activation - washing - speeding - washing chemical copper - washing - the next process
A, the role of copper:
A layer of metal copper is covered in the drilled hole to realize the circuit connection between the PCB layer and the layer and realize the plug welding effect at the customer.
B, to drill the dirt:
The removal of the smudging is achieved by oxidizing the swelled resin in the pores under a certain temperature and concentration condition by the potassium permanganate solution. (Drilling is the resin residue in the hole when drilling)
Full plate plating (one copper plating)
A layer of metallic copper is deposited by electrolysis in the pores after the copper has been deposited to achieve reliable interconnection of the interlayer patterns.
Outer graphics
The pre-treated board is pasted with a photosensitive layer (adhesive film), and aligned by a film pattern, and then the aligned PCB board is sent to an exposure machine for exposure, and then the unreacted photosensitive layer is dissolved by a developing machine. The desired line pattern is finally obtained on the copper plate.
Production process:
Pre-treatment - lamination - alignment - exposure - development QC inspection - the next process
A, pre-treatment (volcanic ash grinding board):
The board completed by the plate is sent to the grinding machine, the grease and oxide layer on the copper surface are removed with a 3%-5% weak acid solution, and the copper surface is polished by a high-temperature rotating brush with a 15-20% volcanic ash solution. Therefore, a relatively uniform copper surface roughness is obtained, and the residual volcanic ash particles in the copper surface and the pores are washed out by washing, and then the surface of the PCB and the water in the pores are dried by the drying section to prevent the copper surface from being oxidized again.
B, stick dry film:
First, the polyethylene protective film is peeled off from the dry film, and then the dry film resist is pasted on the copper clad plate under heat and pressure, and the resist layer in the dry film is softened by the hot tears. The fluidity is increased, and the film is completed by the pressure of the hot press and the action of the binder in the resist.
C, exposure:
Under the irradiation of ultraviolet light, the photoinitiator absorbs the light energy to decompose into a free radical, and the radical further initiates a polymerization crosslinking reaction of the photopolymerizable monomer, and forms a stereoscopic macromolecular structure insoluble in the weak base after the reaction.
D, development:
The active group in the unexposed portion of the photosensitive film reacts with the weak alkali solution to form a soluble substance, and the unexposed photosensitive film is dissolved in the reaction solution, and the exposed photosensitive film is not reacted with the weak alkali solution to be retained. Thereby obtaining the desired line pattern.
Graphic plating (secondary copper plating)
A, plating definition:
Electroplating is the process of using a current to deposit a metal or alloy on the surface of a workpiece to form a uniform, dense, well-bonded metal layer.
B, plating purposes:
Increase the thickness of the coating in the wire and the hole, and improve the electrical properties and physical and chemical properties of the coating in the hole. The function of the tin-plating process is to provide a protective coating to protect the copper wire of the pattern portion from being corroded by the etching solution.
Etching
A, principle:
The unprotected copper is chemically dissolved, leaving the protected copper, and the protective layer (tin layer) on the wiring layer is removed, and finally the desired wiring pattern is obtained on the optical copper plate.
B, production process:
Release board - peeling film - washing - etching - washing - tinning - washing - drying - QC inspection - the next process
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
The design of the buffer stop is dependent, in part, on the kind of couplings that the railway uses, since the coupling gear is the first part of the vehicle that the buffer stop touches. The term "buffer stop" is of British origin, since railways in Great Britain principally use buffer-and-screw couplings between vehicles.
Buffer Block
Buffer Block,Rubber Shock Absorber,Coupling Spiders,Rubber Damper
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