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wood PCB backing board
PCB backup board
drill backup board Have a certain surface hardness (reach to 80+-2 shore)to ensure. that the machine drills bit removal chip to keep the drill holes wall clear and reduce the drilling burr. but not too hard and wear the drill bit to protect the pcb driller.
drilling printed base material made of wood fibre, which has no resin composition. and this drill bed does not produce the melting resin ball adhering to the holes wall. when high speed mechanical drilling.
this printed circuit exit material has certain heat conduction function. which takes away the heat generated during board drilling. reduces the high temperature of the drill bit during speed drilling. and prevents annealing of the drill bit.
Ideal exit material for high precision pcb manufacturing. Material uniformity, less impurities, no metal impurities. in line with ROHS standards.
Thickness tolerance of this product controlled within (+0.15mm) to . avoid frequent change of drilling machine bit height during pcb panels drilling.
pcb hole size can within 0.3mm.The performances of drilling holes are . higher than those of non-professional rotary perforated wood fiberboard. medium density PN wood fiberboard. high density PS wood fiberboard and resin wood fiberboard. which are close to phenolic pcb board. drill size. drill diameter can less than 0.3mm
pcb board custom service such as drills registration holes. cut to size also provide for back drill pcb.
wood backing board advantages
WOOD Backing board for high speed circuit board PCB drilling machine
2.0mm wood backing board designed for automatic PCB DRILING machine.
excellent underlay board no chipping. and free burr properties means lower risk of flute blocking and drill breakage
Reduced friction causes less wear on drill cutting edges, improving drill quality
Reduced drill burr due to a smooth, hard and very thin overlay
No phenolic or resin content to contaminate holes
Excellent flatness and tight thickness tolerances
Suitable for all drill hole size
Usable on both sides without loss of quality. because of symmetrical build-up unique to
PCB back up material feature
Melamine Fibreboard Backup Materials wrapped in a moisture protective packing. and should remain in its original packing until use. It should stored under controlled temperature and humidity conditions . that are like those that surround the production area. Rapid change of these conditions may result in warp.
hole wall roughness ≤ 30μm. hole position offset ≤ 75μm. hole position accuracy CPK ≥ 1.33, and the nail head is. less than twice the inner layer copper thickness.I drill wear, drill broken. and burr.
for the pcb hole size 0.15mm hole . the drilling performance of the backup board :phenolic paper pad. > hot pressing melamine backup board >. fast pressing type melamine wood board > Cold-laid melamine wood mat. > phenolic wood mat ≈ UV plain board > high-density wood-fiber board.
backing boards history
It is well known that in drilling printed circuit boards. it is usual to use dummy boards on either side or both sides of the board or boards to drilled. These dummy boards are sometimes referred to as backing and entry boards. A backing, or back-up, board disclosed in U.S. Pat. No. 3,700,341, comprising a laminate of aluminum foil bonded to Masonite, a fibrous board. A laminated entry board disclosed in U.S. Pat. No. 4,311,419. When many boards are being drilled they are usually made up in stacks. consisting of an entry board on top of the printed circuit board material.
There are many reasons for this-one of these is to reduce burring. another to prevent damage to the top laminate in the stack. and another to improve drilling accuracy. At the bottom of the stack there is usually another board called the back-up board. which is there for many reasons. one of which being to prevent the drills drilling into the base tooling plate. of the drilling machine. and another being to prevent burring of the printed circuit board material. Various materials used for the dummy boards. but the most common dummy boards are composite boards consisting of a metal cladding on one. or both sides of a softer. often organic, sheet of material. The metal is and bonded to the substrate or substrate by means of a permanent adhesive such as an epoxy resin.
Large quantities of these cladded boards are in use. and the difficulty of their disposal is a matter for concern. The metal component makes it difficult to dispose of the used boards. and the strong adhesion of the metal. makes it difficult to reclaim same . Strong adhesion has considered to be important for the rigidity of the board. and for its resistance to the torsion of the drill bit. There is thus an environmental problem. as well as an economic problem through the failure to recycle the dummy boards.
The invention overcomes this problem by providing a composite entry . or backing board for use adjacent a printed circuit board during drilling therethrough. in which the adjacent faces of two laminar components of the entry board joined. such that there is no relative slip during transportation, cutting and positioning. and such that they are separable by peeling them apart after use.
the two laminar components are a substrate. which may be fibrous board or paper, and a metal or metal alloy foil or sheet. typical thickness ranges being 0.1-4 mm and 0.02-1 mm. The substrate thickness is at least 0.020 mm, at least 0.20 mm. and often at least 0.5 mm, and the foil or sheet is at least 0.04 mm thick. The laminar components joined by an intermediate layer or a low-strength. permanent tack, adhesive; or, a similar result. may achieved using an intermediate double-sided adhesive tape. The adhesive materials in each case. should coupled less to the metal or metal alloy component. where one used. than to the other laminar component, so that it may more recycled.
Or, the laminar components may joined by keying together their opposed surfaces. by for example roughening or texturing one. or both surfaces and pressing them together. Thus the laminar components joined face to face without any intermediate adhesive.
The join between the laminar components need not extend over their whole area. but may take effect in strips. or spots or other partial areas. provided there is enough regidity for the intended application.
Another problem associated with the drilling of printed circuit boards. has been the effect of the board material on the drill bit. Circuit boards contain much epoxy resin. During the drilling operation the resin becomes bonded to the margins. and flutes of the drills. This increases the power need. the heat input and causes smearing inside the drilled holes. In some cases the resin build up limits the useful life the drills. The resin can be difficult and expensive to remove when drills are being refurbished.
According to another aspect of the invention. thus, an entry board for use adjacent a printed circuit board (PCB). during drilling therethrough comprises a PCB-engaging sheet adapted to resist burr-formation during drilling. characterised in. that it laminated with a non-metallic sheet over. whose surface distributed a drill lubricant. Where the entry board comprises a paper board. the lubricant can incorporated into the paper.
The lubricant may be any dry film lubricant. such as graphite, molybdenum disulphide or polytetrafluoroethane (ptfe). and it may interspersed in the material during manufacture. or it may applied by brushing, rollcoating. or spraying, or by any other coating method such as the "air knife". The lubricant may or incorporated within the adhesive before application. The preferred lubricant is ptfe.
the entry board comprises the said non-metallic sheet. and a further sheet as two laminar components whose faces joined. such that there is no relative slip during transportation, cutting. and positioning, and such that they are separable by peeling them apart. Thus the non-metallic sheet, for example constituting a substrate of a fibrous board. provided with the drill lubricant. on the surface which faces away from the further sheet. which in preferred embodiments is aluminium.
The drill lubricant reduces or eliminates resin build-up on the drill bit. and helps to prolong the useful drill life. and reduce smearing in the drilled hole.
In another aspect, the invention provides a method of. drilling a printed circuit board. comprising placing an entry. or backing board by either aspect of the invention defined. above next to the printed circuit board. and drilling through both boards. In the case where the entry or backing board has two laminar components. the method includes the further step of peeling off. one of the laminar components, i.e. the metal/metal alloy component. when such used, of the board for reclamation.
In this embodiment of the present invention, a metal layer may removed from a substrate after use. thus allowing the substrate to disposed of and the metal reclaimed. Or the substrate may reused in some applications. Referring to FIG. 1, a weak bond between the metal A and the substrate B may achieved. by means of a low strength adhesive applied to one or both of the contacting surfaces. or by an interposed double-sided adhesive tape. or by treatment of the surfaces in a way which gives some degree of mechanical keying between them. It is not necessary that the bonding extends completely across the surfaces.
PCB drill Backing board supplier - Yueshan
Our modern and world-class infrastructure unit located in FOSHAN. GUANGDONG and boasts of having the latest machinery. and technology to help us manufacture an impeccable product range.
Our products manufactured in compliance with industrial quality standards using qualitative raw materials
Our products undergo stringent checks on their quality. before dispatch to ensure greatest client satisfaction
Yueshan PCB manufacturing backup board. entry board . melamine coated board. melamine drilled panel
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