RU2551368C1 - Method of cutting long-length printed cable - Google Patents

Abstract

FIELD: printing industry.

SUBSTANCE: in the method of length cutting of the printed cable the preliminary roll preform is isolated, then in the interwire gap the process slot is formed, into which the cutting element is inserted. Then, power is supplied to it, bringing to the predetermined temperature regime, then the displacement of the heated cutting element is carried out along the longitudinal axis of the printed cable.

EFFECT: provision of quality longitudinal cut in the interwire gap without compromising the integrity of the side insulation on the cut printed cables, reduction of defects, complexity and cost of production.

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Description

The invention relates to the manufacture of long printed cables with thermoplastic varnish or film insulation, and more particularly to cutting a group blank into individual printed cables, which by definition are a special case of printed circuit boards.

So, for example, in GOST 23752-79 "PCBs. General specifications "the term" flexible printed cables (GPC) "is mentioned in almost all sections of the standard, starting with the preamble.

On modern equipment, the photochemical processes of obtaining all the elements of the board on both a rigid and a flexible base occur in a group workpiece of 400 × 400 mm in size. In this case, the group blank is based on reference holes, and the finished boards are cut out of it by a stamp.

However, this technology is unacceptable for cutting a group blank of long printed cables - a newly created passive electric element as part of the objective process of ERA miniaturization. For the group blank of long flexible printed cables is a tape more than 20 m long, about 100-200 mm wide and 0.1-0.2 mm thick, and the step of the printed conductors in the most common version is 1.25 mm with the width of the printed conductor 0.7 mm and, accordingly, the magnitude of the inter-conductor gap is 0.5 mm.

Known patent of the Russian Federation No. 2342813 from 12/27/2008, in which the cutting of the group blank into separate flexible printed cables is carried out at the place of the remote conductor. This operation is only possible on printed cables with thermosetting varnish insulation.

Also known is USSR author's certificate No. 911748, H05K 3/06 of 03/07/1982, in which separate printed conductors adjacent to a future cable to be cut are removed from printed batch cables with thermoplastic adhesive and film insulation from a group blank. This method creates a fairly free zone for slitting the workpiece into separate cables. Moreover, cutting can be done manually with scissors with a low probability of damage (notching) of the side insulation of the cable. However, the process of removal (peeling) of individual printed conductors from galvanic copper with a thickness of the order of 50 μm, and even with local heating of the printed conductor at the place of peeling, is very laborious, and due to the low mechanical strength of an individual conductor often leads to its breakage, which is generally unacceptable for small batch production. And the device for its mechanization is very difficult and expensive.

Common features of the method proposed by the authors for cutting a long printed cable is the presence of thermoplastic insulation and local heating.

Unlike the prototype, in the method proposed by the authors, a separate conductor that separates the cables adjacent to the group blank is not removed, and its side edges serve as guides for the movement of the cutting element, for example wire.

Thus, the objective of this technical solution was to create a mechanized method for the longitudinal cutting of long printed cables with thermoplastic insulation, which allows to ensure a high-quality longitudinal cut in the interconductor gap without violating the integrity of the side insulation on the cut-out printed cables, as well as to reduce rejects, labor and the cost of their manufacture.

This goal is achieved in that the process of cutting a long printed cable with thermoplastic insulation, containing parallel and rectilinear printed conductors separated by an inter-conductor gap, and the interaction with the cutting element is that the blank of the printed cable is isolated from the forming side of the printed conductors, then on the printed a technological slot is formed in the cable in the interconductor gap, into which the heating element is introduced, then power is supplied to it, After a predetermined temperature regime, then the heated cutting element is moved along the longitudinal axis of the printed cable.

In special cases, that is, in specific forms of execution, the invention is characterized by the following features:

- the cutting element is made in the form of a wire,

- at least one of the fastenings of the cutting element after it is inserted into the inter-conductor gap is pushed towards the removable printed conductor,

- cutting is carried out by two cutting elements,

- both cutting elements are located on the cross section of the cut-out printed cable,

- the cutting elements are moved apart during cutting,

- when cutting, press the heated cutting element to the side edge of the removed printed conductor,

- the width of the cutting element is chosen less than the width of the interconductor gap,

- the temperature regime of the cutting element is chosen between the points of flow and destruction of the insulating material.

It is this that allows us to conclude that there is a causal relationship between the totality of the essential features of the claimed technical solution and the achieved technical results.

The indicated features distinctive from the prototype and to which the requested object of legal protection applies are sufficient in all cases.

When implementing the method for cutting long flexible printed cables, the new sequence of operations and their essence allow, in particular, by insulating the printed cable before cutting it and using the removable printed conductor as a guide support for the heated cutting element, to ensure high-quality longitudinal cut in the interconductor gap without breaking integrity lateral insulation on cut-out printed cables, as well as reduce marriage, labor intensity and cost of their manufacture.

Special cases, that is, specific forms of execution, allow:

- the cutting element is made in the form of a wire - there is no need to base the heating element, for example in a flat design, relative to the longitudinal axis of such a flexible and elastic part as a flexible printed cable. In addition, a heated wire having a much lower mass, unlike a more developed heating element, has less thermal inertia. This makes it possible to localize the width of the cut, preventing melting in the interconductor gap of the material remaining and insulating the side surface of the extreme working conductor of the printed cable, i.e. minimize the width of the cut;

- at least one of the fastenings of the cutting element after it is inserted into the inter-conductor gap is pushed towards the removable printed conductor, this allows the cutting element to be pressed against the removable printed conductor;

- cutting is carried out by two cutting elements, which allows to increase the productivity of the cutting process;

- both cutting elements located on the cross-section of the cut-out printed cable balance the lateral components of the forces arising in each place of the cut separately;

- the cutting elements are moved apart during cutting, which allows you to simultaneously cover both cut printed conductors in an arc;

- ensures that the cutting element is pressed against the side edge of the cut-off printed conductor, this allows you to save the width and electrical properties of the remaining insulation in the inter-conductor gap adjacent to the extreme side printed conductors of the cut-out cable;

- the wires are chosen less than the width of the interconductor gap, in the event that the extreme printed conductors are working, and not technological;

- the temperature regime of the heating element is selected between the points of flow and destruction of the insulating material, which allows to reduce the forces arising in the cutting zone.

Thus, the new sequence of operations and their nature make it possible, in particular, by insulating the printed cable to cut it and using the cut-off printed conductor as a guide support for the cutting element, to ensure a high-quality longitudinal cut in the inter-conductor gap without violating the integrity of the side insulation on the cut-out printed cables , as well as reduce the marriage, the complexity and cost of their manufacture.

Based on the proposed method for thermal cutting of a long-length printed cable with thermoplastic insulation, a technological process for the manufacture of printed cables has been developed and introduced into mass production.

Claims (4)

1. The method of cutting a long printed cable with thermoplastic insulation, containing parallel and rectilinear printed conductors separated by an inter-conductor gap, by interacting with a cutting tool, characterized in that the pre-blank of the printed cable is isolated from the forming side of the printed conductors, then a technological slot is formed in the inter-conductor gap into which the cutting tool is introduced, pushing one of its fasteners towards the cut-off printed conductor, then on p cementitious tool is energized, bringing to a predetermined temperature, and then heated is moved cutting tool along a longitudinal axis of the print cable. 2. The method according to p. 1, characterized in that the cutting tool is made in the form of a wire. 3. The method according to p. 1, characterized in that when cutting the heated cutting tool is pressed against the side edge of the removable printed conductor. 4. The method according to p. 1, characterized in that the temperature of the heating of the cutting tool is chosen between the points of flow and destruction of the insulating material.