EP0077781A1 - Backup material for drilling - Google Patents

Backup material for drilling

Info

Publication number
EP0077781A1
EP0077781A1 EP82901033A EP82901033A EP0077781A1 EP 0077781 A1 EP0077781 A1 EP 0077781A1 EP 82901033 A EP82901033 A EP 82901033A EP 82901033 A EP82901033 A EP 82901033A EP 0077781 A1 EP0077781 A1 EP 0077781A1
Authority
EP
European Patent Office
Prior art keywords
drilling
backup material
paper
facing
backup
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP82901033A
Other languages
German (de)
French (fr)
Inventor
Nils Göran Boris ANDERSSON
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
B R A Kemisk Frasning
Original Assignee
B R A Kemisk Frasning
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by B R A Kemisk Frasning filed Critical B R A Kemisk Frasning
Publication of EP0077781A1 publication Critical patent/EP0077781A1/en
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B35/00—Methods for boring or drilling, or for working essentially requiring the use of boring or drilling machines; Use of auxiliary equipment in connection with such methods
    • B23B35/005—Measures for preventing splittering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/28—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer comprising a deformed thin sheet, i.e. the layer having its entire thickness deformed out of the plane, e.g. corrugated, crumpled
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27G—ACCESSORY MACHINES OR APPARATUS FOR WORKING WOOD OR SIMILAR MATERIALS; TOOLS FOR WORKING WOOD OR SIMILAR MATERIALS; SAFETY DEVICES FOR WOOD WORKING MACHINES OR TOOLS
    • B27G19/00—Safety guards or devices specially adapted for wood saws; Auxiliary devices facilitating proper operation of wood saws
    • B27G19/10—Measures preventing splintering of sawn portions of wood
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/12—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of paper or cardboard
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/0011—Working of insulating substrates or insulating layers
    • H05K3/0044—Mechanical working of the substrate, e.g. drilling or punching
    • H05K3/0047—Drilling of holes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
    • B32B2260/02—Composition of the impregnated, bonded or embedded layer
    • B32B2260/028—Paper layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
    • B32B2260/04—Impregnation, embedding, or binder material
    • B32B2260/046—Synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2317/00—Animal or vegetable based
    • B32B2317/12—Paper, e.g. cardboard
    • B32B2317/127—Corrugated cardboard
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/02—Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0275—Fibers and reinforcement materials
    • H05K2201/0284—Paper, e.g. as reinforcement
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/02—Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0275—Fibers and reinforcement materials
    • H05K2201/0293—Non-woven fibrous reinforcement
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/01—Tools for processing; Objects used during processing
    • H05K2203/0147—Carriers and holders
    • H05K2203/0156—Temporary polymeric carrier or foil, e.g. for processing or transferring
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/02—Details related to mechanical or acoustic processing, e.g. drilling, punching, cutting, using ultrasound
    • H05K2203/0214—Back-up or entry material, e.g. for mechanical drilling

Definitions

  • the present invention relates to a backup material for drilling which consists of a sheet-like laminate and is intended, in relation to a work-table or a similar base, to form a support for a panel-shaped or other pla- nar material when drilling through the material with a drilling tool.
  • the object of the invention is to solve these problems by providing a drilling backup material which has a wavy or fluted central layer to permit sucking off dust and particles from the drill holes and efficiently cooling the drilling tools, and which additionally causes little wear of the tools, which is highly important.
  • Another essential object of the invention is to provide a drilling backup material that is inexpensive, this being also of great importance, especially since
  • Fig. 1 schematically shows a drill with a pres- 10 sure foot, a work-table and a drilling backup material according to the invention for sheets or laminates with printed circuits to be drilled.
  • Fig. 2 is a view similar
  • Fig. 1 there is shown part of a drilling machine with a work-table 1, a pressure foot 2 and a 20 drilling tool 3 for drilling a number of sheets or panels 4 with printed electric circuits, for instance copper circuits on ' glass fibre laminate.
  • the sheets or panels 4 are placed on a drilling backup material 5 according to the invention which itself is placed on 25 the work-table 1.
  • drilling top cover there may be disposed on top of the sheets of panels 4 a thin sheet 6 of a suitable material, for instance phenolic resin- impregnated paper if this is desirable or in a special case is deemed advantageous.
  • This stack consisting of sheets or panels 4 with printed circuits, the backup material 5 and the top cover 6 is held together and maintained at the work- table 1 in a conventional fashion by means of a number of stacking pins 7 which extend through holes in the 35 stack of sheets and backup material and into holes in the work-table 1.
  • the pressure foot 2 is applied against the stack.
  • the pressure foot 2 comprises a housing which sur ⁇ rounds the drilling tool 3 (or each drilling tool) and is connected by an 4 opening 8 and a tube 9 to a suction source ⁇ not shown) for sucking off particles and dust.
  • corrugated board i.e. a paper product consisting of one layer of fluted paper 12 and at least one facing, i.e. single faced corrugated board, or one layer of fluted paper 12 and two facings 11, 14, i.e. double faced corrugated board.
  • the flute tubes 10 can be used as ducts for air through-flow in the drilling backup material and for sucking off dust and particles through the drill hole and by the pressure foot 2 to the dust extractor as soon as the tip of the drilling tool 3 has penetrated through the top facing 11 of the corrugated board.
  • the air flow from the flute tubes 10 through the drill hole is immediately initiated when the drilling tool 3 punctures the facing 11, and the upward air stream, for instance a helical flow along the twist drill 3, will effectively clean both the drilling tool and the edges of the drill hole and further has the beneficial effect of effectively cooling the drilling tool immediately after a drilling operation has been performed and during the withdrawal of the drilling tool, dust and particles detached from the material and the drilling tool being sucked off during the extraction of the drilling tool.
  • OMPI ous in so far as it gives, for . a desired small total amount of material and weight, a relatively great thickness to provide the desired distance between the material 4 to be drilled and the work-table 1. 5 Particles that are not sucked upwards and out of the housing 2 when the drill tip has penetrated through the top facing 11 of the panel of corrugated board are not entrapped in the drill hole proper, from where they could penetrate in between the sheets 4 and the backup 10 material, but can fall freely into the empty spaces defined by the flute tubes 10.
  • Corrugated board being a paper product, one might 30 believe that dust and fibres would loosen and contaminate or completely ruin the printed circuit boards. Even if the dust extraction as described with reference to Fig. 2 would produce a certain effect, it was believed that the drilling tools in all likelihood would ruin 35 the printed circuit boards by fraying the edges of the drill holes and cause flocculation of loose fibres which by the extraction of the drilling tools are pulled
  • corrugated board is an inex ⁇ pensive material which in standard qualities is manufac ⁇ tured in thicknesses that are suitable and with flute tubes that are sufficiently large to ensure the above- described dust extraction and air cooling.
  • Phenolic resin can readily be applied to the facing or facings by spraying or perfusion, which should and can easily be so performed that the glue joints of the corrugated board are not dissolved but rather, upon curing of the resin, are strengthened at the flute crests and without the flute tubes being clogged and thus obstructed.
  • the material is cured in a furnace, for instance for about 40 min. or more at about 170°C de ⁇ pending on the basis weight of the corrugated board and
  • the drilling backup board As basic material for the drilling backup board according to the invention use is preferably made of corrugated board of standard quality with a thickness of at least 1 mm and most preferably between 1.5 and 3
  • corrugated board with a thickness of 2 mm requires phenolic resin with setting agent in an
  • the production costs for the backup material according to the invention will then amount approximately to only about 10-25 % of the pro ⁇ duction costs for the drilling backup materials which have hitherto been used and of which the backup material composed of one layer of fluted metal foil and two
  • the backup material according to the invention is an improvement in all respects contemplated herein and, as far as is known, inferior in no other respect. Above all, the material according to the invention is far more gentle with respect to the drill in that the facing or cover layer of paper is hard after impregnation, yet brittle and readily punctured by the drill tips, forming clean hole edges without burrs during drilling.
  • the cured resin will not soften and will entail no tendency to sticking at prevailing temperatures which can be kept relatively low by the reduced penetration work, which will entail less wear and extended tool life.
  • the foregoing description has been concerned with printed electric circuits, circuit boards etc., but it goes without saying that the drilling backup - aterial according -to the invention is also useful in the drill ⁇ ing of other materials in which the problems encountered are equivalent to those met with in conjunction with the drilling of boards with printed electric circuits, and in paifticular where it is vital that the temperature of the drilling tools is kept relatively low.
  • Good results are possible to obtain according to the invention also with resinous impregnating agents other than phenolic resin, such as epoxy resin, phenolic resin being however preferred since, among other things, it is relatively . inexpensive. For the same reason, corrugated board of any commercial type is preferred.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
  • Drilling And Boring (AREA)
  • Laminated Bodies (AREA)

Abstract

Materiau de protection pour percage consistant en un lamine qui est essentiellement constitue d'une couche de papier cannele (12) et de placages (11, 14), a savoir du carton ondule, par exemple du carton ondule a une seule face ou paroi, lesquelles couches d'au moins du ou des placage(s) colle(s) sont impregnees d'une composition resineuse, telle qu'une resine phenolique, qui se polymerise apres impregnation.Protective material for piercing consisting of a laminate which essentially consists of a layer of corrugated paper (12) and veneers (11, 14), namely corrugated cardboard, for example corrugated cardboard with only one face or wall, which layers of at least one or more glued plating (s) are impregnated with a resinous composition, such as a phenolic resin, which polymerizes after impregnation.

Description

BACKUP MATERIAL FOR DRILLING
The present invention relates to a backup material for drilling which consists of a sheet-like laminate and is intended, in relation to a work-table or a similar base, to form a support for a panel-shaped or other pla- nar material when drilling through the material with a drilling tool.
In the drilling of panels, sheets, boards, cards or the like consisting of for instance laminates of resin-impregnated glass fibres with printed electric circuits for making drill holes to permit passing leads, connections etc. therethrough, it is of importance that the material be drilled without damaging the edges of the holes and without leaving cuttings adhering to the material. It is therefore necessary during the drilling operation to support the material, and it is known in the art to use drilling backup materials as a protective support between the work-table and the material in order to prevent the tip of the drill from penetrating down into the work-table and to prevent the formation of copper burrs at the exit side of the hole of the drilled material. It has been proposed to use as drilling backup materials laminates made up of board and glass fibre fabric attached to the board by means of epoxy resin or other resinous binders, the problem being however that the drill tip, when drilling through a stack of glass fibre laminates with printed circuits, backup material and possibly also a drilling top cover, is heated to a relatively high temperature, for instance up to 250°C or more, whereby the drill tip will tend to melt the binder both in the circuit board laminates and in the backup material so that it becomes sticky with an ensuing increased tendency to contamination. In addition, the edges of the drill holes may soften and increase the tendency to formation of copper burrs. In order to over¬ come these problems it has been suggested to replace the glass fibre fabric with metal foil glued on both sides of a wood fibreboard. The metal foils, usually aluminium foils, were expected to reduce the tendency of the wood fibreboard to warp, and produce a cooling and clean¬ ing effect on the drill tip.
In experiments conducted in connection with the conception of this invention, a vast number of laminates were tested, using cover layers of metal foil, however with disappointing results. It was found that the useful¬ ness of the capacity of the metal foil to abduct heat from the drill tips was negligible in comparison with the substantial adverse effect of the metal foils caus- ing more extensive wear and heating of the drill tips by frictional engagement therewith than did the printed circuit boards.
It was therefore necessary in some way to cool the drilling tools and so it was suggested to replace the wood fibreboard forming the central layer of the drilling backup material with an undulating metal foil and to suck air through the flute ducts and the drill hole along the drilling tool during the extraction thereof. Unfortunately, the drilling tools were su jec- ted to even greater wear and heating when they had to penetrate through an additional metal foil, which to a great extent took away the effect of an otherwise efficient air cooling.
The object of the invention is to solve these problems by providing a drilling backup material which has a wavy or fluted central layer to permit sucking off dust and particles from the drill holes and efficiently cooling the drilling tools, and which additionally causes little wear of the tools, which is highly important. Another essential object of the invention is to provide a drilling backup material that is inexpensive, this being also of great importance, especially since
OMPI " the service life of a drilling backup material is rather short.
These objects have now been achieved in that the drilling backup material according to the invention has 5 been given the features stated in claim 1 and optionally the improvements stated in claims 2-5.
The invention will be described in greater detail hereinbelow with reference to the accompanying drawings, in which Fig. 1 schematically shows a drill with a pres- 10 sure foot, a work-table and a drilling backup material according to the invention for sheets or laminates with printed circuits to be drilled. Fig. 2 is a view similar
( _- to that of Fig. 1 but shows the drilling backup material in a section at right angles to that of Fig. 1, i.e. 15 along the flute tubes, and Fig. 3 on a larger scale shows a section of the drilling backup material accord¬ ing to the invention.
In Fig. 1, there is shown part of a drilling machine with a work-table 1, a pressure foot 2 and a 20 drilling tool 3 for drilling a number of sheets or panels 4 with printed electric circuits, for instance copper circuits on' glass fibre laminate. The sheets or panels 4 are placed on a drilling backup material 5 according to the invention which itself is placed on 25 the work-table 1. As drilling top cover, there may be disposed on top of the sheets of panels 4 a thin sheet 6 of a suitable material, for instance phenolic resin- impregnated paper if this is desirable or in a special case is deemed advantageous. 30 This stack consisting of sheets or panels 4 with printed circuits, the backup material 5 and the top cover 6 is held together and maintained at the work- table 1 in a conventional fashion by means of a number of stacking pins 7 which extend through holes in the 35 stack of sheets and backup material and into holes in the work-table 1. To perform drilling the pressure foot 2 is applied against the stack.
OMPI The pressure foot 2 comprises a housing which sur¬ rounds the drilling tool 3 (or each drilling tool) and is connected by an4 opening 8 and a tube 9 to a suction source {not shown) for sucking off particles and dust. It has surprisingly been found that the problems described by way of introduction can be overcome in all prior art drilling backup materials simply by using corrugated board, i.e. a paper product consisting of one layer of fluted paper 12 and at least one facing, i.e. single faced corrugated board, or one layer of fluted paper 12 and two facings 11, 14, i.e. double faced corrugated board. The flute tubes 10 can be used as ducts for air through-flow in the drilling backup material and for sucking off dust and particles through the drill hole and by the pressure foot 2 to the dust extractor as soon as the tip of the drilling tool 3 has penetrated through the top facing 11 of the corrugated board.
The air flow from the flute tubes 10 through the drill hole is immediately initiated when the drilling tool 3 punctures the facing 11, and the upward air stream, for instance a helical flow along the twist drill 3, will effectively clean both the drilling tool and the edges of the drill hole and further has the beneficial effect of effectively cooling the drilling tool immediately after a drilling operation has been performed and during the withdrawal of the drilling tool, dust and particles detached from the material and the drilling tool being sucked off during the extraction of the drilling tool.
Such air cooling efficient per se would however not give an overall advantage if the drilling backup material, in order to ensure the air cooling, were to cause an increase in wear and, as a result thereof, increased frictional heating of the drilling tool. The material according to the invention however only slightly affects the drilling tools and additionally is advantage-
OMPI ous in so far as it gives, for. a desired small total amount of material and weight, a relatively great thickness to provide the desired distance between the material 4 to be drilled and the work-table 1. 5 Particles that are not sucked upwards and out of the housing 2 when the drill tip has penetrated through the top facing 11 of the panel of corrugated board are not entrapped in the drill hole proper, from where they could penetrate in between the sheets 4 and the backup 10 material, but can fall freely into the empty spaces defined by the flute tubes 10.
To sum up, it has been found that heat conducting mJ metal foils only theoretically enhance the cooling effect on the drill tip itself by abduction of heat. 15 whereas they subject the drill tip to increased wear, this being per se a considerable drawback, and that the heating of the tool will thus also increase. The invention rebuts the theory that contact between drill tip and heat-abducting metal is necessary to ensure 20 cooling down to a desired low level, and also the theory that a thin aluminium foil causes little wear, and has demonstrated that corrugated board, strengthened with a suitable resin, will give superior results in every respect. 25 The drilling backup material 5 shown in Fig. 3 consists of resin-coated double faced corrugated board on which an extra outer layer 13 is glued for additional strengthening.
Corrugated board being a paper product, one might 30 believe that dust and fibres would loosen and contaminate or completely ruin the printed circuit boards. Even if the dust extraction as described with reference to Fig. 2 would produce a certain effect, it was believed that the drilling tools in all likelihood would ruin 35 the printed circuit boards by fraying the edges of the drill holes and cause flocculation of loose fibres which by the extraction of the drilling tools are pulled
OMPI
/>,„ WHO - 6 up into the holes to stick there. Panels of ordinary corrugated board would in addition make an unstable support which might permit movement of one facing with respect to the other and hence make the material use- less as a backup material for drilling. The very rapid, accurate drillings which are performed in the drilling of printed circuit boards and are very similar to punch¬ ing, in fact require an immobile backup material, i.e. backup material which neither is movable laterally nor ' warps. On the other hand, corrugated board is an inex¬ pensive material which in standard qualities is manufac¬ tured in thicknesses that are suitable and with flute tubes that are sufficiently large to ensure the above- described dust extraction and air cooling. According to the invention, it has been found that ordinary corrugated board of standard quality can be strengthened and improved by a relatively simple and relatively inexpensive treatment, so as to make a superior drilling backup material as compared with facings of metal foil with a sandwiched layer of fluted metal foil. This is achieved by strengthening the corrugated board with resin. Phenolic resin in particu¬ lar has proved to impart the desired strength and stabi¬ lity to corrugated board. Furthermore, this type of resin has the property of making the cover layers or facings relatively brittle so that they can be readily punctured by the drilling tips, giving holes with clean sharp contours. Phenolic resin can readily be applied to the facing or facings by spraying or perfusion, which should and can easily be so performed that the glue joints of the corrugated board are not dissolved but rather, upon curing of the resin, are strengthened at the flute crests and without the flute tubes being clogged and thus obstructed. After application of the phenolic resin, the material is cured in a furnace, for instance for about 40 min. or more at about 170°C de¬ pending on the basis weight of the corrugated board and
OMPI the amount of resin applied.
As basic material for the drilling backup board according to the invention use is preferably made of corrugated board of standard quality with a thickness of at least 1 mm and most preferably between 1.5 and 3
2 mm and a basis weight of between about 150 g/m and 2
280 g/m for both fluted layer and facing before the impregnation with phenolic resin.
As an example of the degree of impregnation, it may be mentioned that corrugated board with a thickness of 2 mm requires phenolic resin with setting agent in an
2 amount of about 0.125 1/m for optimum results and im¬ pregnation on both sides. The production costs for the backup material according to the invention will then amount approximately to only about 10-25 % of the pro¬ duction costs for the drilling backup materials which have hitherto been used and of which the backup material composed of one layer of fluted metal foil and two
2 facings of metal foil will cost about 100 crs/m in manufacture, to be compared with a cost of about 10 crs/m^ for the impregnated and cured material according to the invention as described above. In addition, the backup material according to the invention is an improvement in all respects contemplated herein and, as far as is known, inferior in no other respect. Above all, the material according to the invention is far more gentle with respect to the drill in that the facing or cover layer of paper is hard after impregnation, yet brittle and readily punctured by the drill tips, forming clean hole edges without burrs during drilling. The cured resin will not soften and will entail no tendency to sticking at prevailing temperatures which can be kept relatively low by the reduced penetration work, which will entail less wear and extended tool life. The foregoing description has been concerned with printed electric circuits, circuit boards etc., but it goes without saying that the drilling backup - aterial according -to the invention is also useful in the drill¬ ing of other materials in which the problems encountered are equivalent to those met with in conjunction with the drilling of boards with printed electric circuits, and in paifticular where it is vital that the temperature of the drilling tools is kept relatively low. Good results are possible to obtain according to the invention also with resinous impregnating agents other than phenolic resin, such as epoxy resin, phenolic resin being however preferred since, among other things, it is relatively . inexpensive. For the same reason, corrugated board of any commercial type is preferred.

Claims

1. A panel-shaped backup material for* rilling, consisting of a laminate and intended, in relation to a work-table (1) or the like, to support a panel-shaped or other planar material when drilling through the mate- rial with a drilling tool (3), c h a r a c t e ¬ r i s e in that the drilling backup laminate consists of a panel of corrugated board comprising at least one facing of paper and one layer of fluted paper fixed thereto, and that of these paper layers at least the facing, for stiffening the panel of corrugated board, is impregnated with a curable resin which is cured after the impregnation. •
2. Drilling backup material as claimed in claim 1, c h a r a c t e r i s e d in that the resinous compo- sition is a phenolic resin composition.
3. Drilling backup material as claimed in claim 1 or 2, c h a r a c t e r i s e d in that the corruga¬ ted board, prior to impregnation, has a thickness of between 1 and 4 mm and that as facing or cover layer
2 it uses a paper with a basis weight of 150-280 g/m , the layer of fluted paper preferably also being a
2 paper with a basis weight of 150-280 g/m .
4. Drilling backup material as claimed in claim 1, c h a r a c t e r i s e d in that an additional facing (13) is fixed on the outer side of one facing (11) to ensure further stiffening.
5. Drilling backup material as claimed in claim 4, c h a r a c t e r i s e d in that the additional facing (13) also consists of a paper impregnated with resin.
- QKE - _ OMPI
EP82901033A 1981-03-23 1982-03-22 Backup material for drilling Ceased EP0077781A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8101814A SE446953B (en) 1981-03-23 1981-03-23 BORRUNDERLEGG
SE8101814 1981-03-23

Publications (1)

Publication Number Publication Date
EP0077781A1 true EP0077781A1 (en) 1983-05-04

Family

ID=20343393

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82901033A Ceased EP0077781A1 (en) 1981-03-23 1982-03-22 Backup material for drilling

Country Status (4)

Country Link
EP (1) EP0077781A1 (en)
JP (1) JPS58500436A (en)
SE (1) SE446953B (en)
WO (1) WO1982003193A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1272337B1 (en) * 2000-03-27 2004-09-29 Arnold B. Finestone Cardboard and corrugated board container having laminated walls
US10399151B2 (en) * 2016-02-17 2019-09-03 The Boeing Company Methods of forming holes in a workpiece and associated systems

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3700341A (en) * 1970-07-27 1972-10-24 Lcoa Laminating Co Of America Laminated board and method of making same
US4269549A (en) * 1979-07-30 1981-05-26 Lcoa Laminating Company Of America Method for drilling circuit boards

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8203193A1 *

Also Published As

Publication number Publication date
WO1982003193A1 (en) 1982-09-30
SE8101814L (en) 1982-09-24
SE446953B (en) 1986-10-20
JPS58500436A (en) 1983-03-24

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Inventor name: ANDERSSON, NILS GOERAN BORIS