WO2018197933A1

WO2018197933A1 - Wear-resistant welding plate

Info

Publication number: WO2018197933A1
Application number: PCT/IB2017/054145
Authority: WO
Inventors: Mitja GOLENKO; Primož GOLENKO
Original assignee: BP BLISTER PACK d.o.o.
Priority date: 2017-04-26
Filing date: 2017-07-10
Publication date: 2018-11-01
Also published as: SI25120A

Abstract

The wear-resistant welding plate (1) addresses the issue of the finishing layer (1.3) wear which occurs during welding. Its intended use is for heat welding of thin polymer strips (3.2) and aluminum alloys (3.1) which are used for product packaging (4) in pharmaceutical and other industries. The surface (1.1) of the top welding plate (1) is constructed with a pyramid-shaped engraving which is determined with the dimensions of the pyramid angle (alpha), pyramid front (a) and pyramid interaxial section (b). A NiP (nickel) layer (1.2) is applied to the welding surface (1.1) of the top welding plate and the finishing layer (1.3) made of hard CrN (chrome-nitride) on top of it which due to its wear resistance significantly increases the service life of the top welding plate (1) and in this way prevents the replacement of the top welding plates (1) because of wearing out. The top welding plate (1) can be clamped to the welding machine guides using the elastic base (5) which is adjusted to the surface of the bottom welding plate (2).

Description

Wear-resistant welding plate

BACKGROUND

[0001] The subject of the invention is a technical system of an extremely wear-resistant welding plate for contact welding polymers without the addition of any welding materials.

The described technical system is intended to extend the useful life/usability of a welding plate for contact polymer welding.

BRIEF SUMMARY OF THE INVENTION AND RELATED ART

[0002] The technical problem solved by the described technical system is the elimination of the contact wear of the welding surface of the welding plate for contact polymer welding.

The state-of-the-art status so far was that in pharmaceutical and other industries the contact welding machines used for welding the packaging of products welded two layers of polymer strips or, in most cases, a layer of the polymer strip and a layer of tape made of aluminum foil. The first tape (polymer layer) may be a PVC-AL-PVC combination of, that is a composite, while the second layer of the tape is always an aluminum foil. The products which are packed in this way and are protected against external influences, such as dirt, humidity, air pressure etc. are welded between tapes into the nest of the bottom tape.

These contact welding machines consist of a top welding plate, bottom welding plate, the travel guide of the top welding plate, the transport of the bottom and top band (both work pieces), the heating system of the top welding plate, an engraving system of the top welding plate through both work pieces to the bottom welding plate.

Due to the heat transfer, the top welding plates are made of aluminum or aluminum alloys, while the bottom welding plates are made of steel.

According to the current state-of-the-art the boards are both made of aluminum or both of steel. Description

For better heat transfer to the work piece, plates made of aluminum or aluminum alloy are used predominantly.

The surface pressure of both welding plates during the welding procedure to bands of both work pieces are equivalent to 5 to 10 bar, while the temperature of the welding plate ranges from 150 to 250 degrees Celsius.

The contours of both welding plates are usually made of so-called pyramids, so that the apexes of the pyramids of the upper welding plate are stamped through both work pieces into the base of the pyramids of the bottom welding plate. In this case it is not strictly necessary that the apexes of pyramids are stamped directly into the base of the pyramids, whereby it is only important that the apexes of the pyramids do not sit onto each other, because in that case damage to the surface areas of the pyramid engraving could occur.

In this case the problems of such welding machines are in that the welding surface - contour 1.1 of the top welding plate 1 due to heating to the operating welding temperature because of the relatively large surface pressures and due to stamping the surface area - contour of the pyramids 1.1, into the work piece 3.1 results in a relatively rapid wear, whereby it causes substandard joints between the work pieces 3.1 and 3.2. The apexes of the so-called pyramids which push against the work piece are prone to wear. Wear is additionally increased due to the temperature to which the top welding plate 1 is heated.

Because of this it is necessary to regularly replace the top welding plates 1 which results in an exorbitant cost since the surface treatment of the top welding plate is very difficult and consequently expensive.

[0003] The state-of-the-art in this field does not use hard application onto welding surface of the top welding plate 1, because of which the overall problem of the state-of-the-art condition is the wear of the bottom surface area of the top welding plate.

There is only one patent that can be found in the SIPO database with the following patent application No.: 9700226, which has the same name as our presented invention. Description

However, this patent deals with high-frequency based welding. The bottom welding plate is executed with longitudinal cut-out sections and is movable. The welding plate which is the subject of this patent is not constructed with a pyramid-shaped contour. That is, it is without a constructed contour which would be prone to wear during stamping in the welding procedure.

Due to this, the patent does not solve the problem which is saved by the presented invention and therefore we can claim that this patent discloses a completely different invention than our presented invention.

Under the welding machine I can find a patent which is published with the following patent application No.: 21996.

This patent deals with the method of optical measurement and the comparison of welds and provides a means for inspecting welds. It determines and publishes the invention of optical weld measurement on the basis of which the optimum welding technology can be determined. This patent is completely different from the proposed technical invention since it does not use the welding plate which would have a pyramid- shaped engraving. Namely, it does not even describe the methods of welding; however, it describes ways to determine the measurements of the already welded work pieces or welds made of metal.

Under the search "welding" you can find many patents in the SIPO patent database, of which some are described below:

A patent published under patent application No.: 24845

It proposes welding of bands. In this case it primarily deals with tensioning, positioning and collision welding.

This patent also does not use a welding plate with an engraving and is completely different from our proposed patent. Description

The patent published under patent application No.: 23667

It proposes the optimization of the vacuum welding machine - for packaging food products. This patent primarily deals with the operation of both parts of the welding machine and the welding plate with a pyramid-shaped engraving is not used. It uses a completely different method and is entirely different from our proposed invention.

The patent published under patent application No.: 21360

It presents thermal sleeve welding where the work piece positions the cylinder. This patent also does not use a welding plate with a constructed pyramid-shaped engraving.

This patent uses a completely different method from our presented invention.

Under the search "welding" you can find many other patents in the SIPO database. However, all of them use different technical solutions from our presented invention.

None of them present the use of welding plates with built-in engraving for impressing the work piece.

DETAILED DESCRIPTION OF THE INVENTION AND BRIEF DESCRIPTION OF THE DRAWINGS

The presented technical invention using the technical invention of applying hard carbide onto the welding surface of the top welding plate. It almost completely eliminates the wear of the welding surface of the welding plate 1.

Figure 1: It shows a schematic illustration of both welding plates: top welding plate 1, bottom welding plate 2; both work pieces: top work piece 3.1, bottom work piece 3.2, product nest 3.3 and welding product 4. An elastic base 5 is visible above the top welding plate 1.

Figure 2: It shows the top welding plate 1 with a pyramid-shaped surface area 1.3 engraving (elevation and plan view) Description

Figure 3: It shows detail A - an enlarged cross-section of the welding surface areas 1.1, 1.2 and 1.3 with visible layers of application and the basic layer of the top welding plate 1.

The essential part of the invention is that the top welding plate was made of copper alloy instead of aluminum alloy which consists of the following: namely of Co=1.0%, Ni=1.0%, Be=0.5%, Fe=<0.2%, SI=<0.2%, Cu=the remainder.

An 8 to 15 micron thick NiP (nickel) layer 1.2 is applied to this basic layer which is shaped in the form of an engraving/pyramid with the dimensions of the pyramid apex a, the interaxial pyramid section b and the alpha angle of the pyramid slopes to which a 1 to 5 micron CrN (chromium-nitride) finish 1.3 is applied.

The basic layer 1.1 must be made with a degree of processing of surface roughness of N4 or finer.

The NiP (nickel) layer 1.2, has the function of distribution of surface pressures as well as the function of a soft layer which prevents the hard application or final CrN (chrome -nitride) 1.3 layer from bursting or cracking and gradually peeling off. Such technology is otherwise known, but it was never used for the purpose which is described by this proposed technical invention.

Therefore, known techniques are used for the application of the NiP (nickel) layer 1.2 using an electrolyte procedure which may be different. It is only important to create a thin NiP (nickel) layer 1.2 the surface area of which is as smooth as the basic pyramid engraving layer 1.1. The application of the layer is outside the scope of this invention; however, this application is used as state-of-the-art but in the product category where it has not yet been used.

Just like the NiP (nickel) application layer 1.2 which is applied to the basic engraving layer with pyramids, you apply the NiP (nickel) layer 1.2 also to the finishing CrN (chrome-nitride) layer 1.3 using already known technological procedures. This finishing layer 1.3 can be further strengthened with a certain amount of thermal processing at 200°C. This method of application is also not the subject of this invention, but it was first used in this product category. Description

It is particularly important that the NiP (nickel) layer 1.2 to which the finishing CrN (chrome- nitride) layer 1.3 - solid carbide - PVD covers application has been used in this product category.

Instead of a finishing layer, 1.3 of a hard carbide can (for example) also be applied to titanium oxide or some other hard application of the PVD coating which has a function of increasing the wear resistance of the surface against the polymer and thus represents the finishing layer 1.3.

It is important, that the basic surface 1.1 of the engraving with pyramids is made in an extremely accurate manner with a degree of surface processing of N4 or finer.

In the event that the basic surface 1.1 was rough, the finishing layer 1.3 would be equally rough or even rougher.

When the surface is rougher than the finishing layer, the greater the friction against the top workpiece 3.1. If the friction is greater, this means that more energy which is partly converted into heat energy and partly into work energy is released on the sliding surfaces, which causes wear on the workpiece 3.1 and the finishing layer 1.3.

For easier understanding, we describe below the workpiece welding procedure 3.1 and 3.2, between which we weld the product 4.

The bottom workpiece, with restructured nests 3.3, into which products 4 are inserted, travels over the bottom welding plate 2. The top workpiece 3.1 with a flat surface travels with equivalent speed above the workpiece 3.2. Both workpieces 3.1 and 3.2 stop at the same time at the welding site, while the top welding plate 1 with its surface 1.3 pushes onto the top workpiece 3.1, and the latter pushes onto the bottom work piece 3.2 which is then laid onto the top surface area 2.1 of the bottom welding plate 2. Due to the temperature which is transferred from the top welding plate 1 to the workpiece 3.1 and 3.2 and the surface pressure of both welding plates on both workpieces 3.1 and 3.2, the two workpieces 3.1 and 3.2 are welded on the contact surfaces, while the item 4 is hermetically welded in the nest 3.3. Description

After compression, the surface area of the finishing layer 1.3, because of the geometry of the pyramids which is marked by the alpha incline angle of the pyramid which ranges from 90 to 160 degrees, partially slides the dimension of the pyramid front (a) ranging from 0.1 mm to 0.5mm and the dimension of the pyramid interaxial section (b) ranging from 0.3 mm to 1.5 mm along the surface of the top workpiece 3.1. This leads to surface tensions between the finishing surface 1.3 of the top welding plate 1 and the surface of the top workpiece 3.1. Because the workpiece 3.1 is in contact with the finishing surface 1.3 of the top welding plate 1 only once since the welding phase is completed in a single cycle no wear to the surface of the workpiece 3.1 occurs. The finishing surface 1.3 of the top welding plate 1 repeats this cycle until the surface of the pyramid engraving wears out.

While using the hard carbide application and thereby forming an extremely wear-resistant finishing surface 1.3 of the top welding plate 1, the wear of this surface in friction along the top workpiece 3.1 is practically eliminated and the service life of thus constructed top welding plate 1 is practically unlimited and is equivalent to the service life of the bottom welding plate 2 which is made of steel and is not heated.

The application layer 1.2 and finishing layer 1.3 are exceptionally thin and are at the same time highly thermally conductive, therefore they do not reduce the heat transfer from the top welding plate 1 to the workpiece 3.1.

It is important that the finishing layer 1.3 of the top welding plate 1 is as smooth as possible due to sliding along the workpiece 3.1, whereby the treatment of the surface 1.1 of the top welding plate 1 must after the treatment level be at least of N4 or finer before the application of the copper layer 1.2.

To apply the finishing layer 1.3, we can also use any other carbide or, for example, titanium oxide or similar, provided that we achieve the hardness of at least 60Hrc.

The thickness D of the top welding plate 1 must be sufficient to provide the rigidity of the finishing layer 1.3 and thereby preventing cracks on the finishing layer 1.3. Therefore, the thickness D of the top welding plate 1 should be at least 10 mm or more. Description

Heating the top welding plate 1 is carried out with the electrical resistance heaters in the area ranging from 150 to 250 degrees Celsius with the temperature tolerance up to 5 degrees Celsius.

Heating the upper welding plate 1 can also be carried using other forms of heating. The single important thing is that the finishing layer 1.3 is heated evenly.

In the case of an unevenly heated finishing layer 1.3 or in case the temperature of the top welding plate 1 would change constantly and relatively quickly, cracks in the finishing layer 1.3 could occur due to the dilations of the basic part of the top welding plate 1.

In the case of cracking the finishing layer 1.3, the friction during engraving into the top workpiece 3.1 will increase due to the cracks. Consequently, the peeling off of the finishing layer 1.3 would occur and subsequently also the wearing of the layer 1.2. After the layer 1.2 wears out the surface area of the pyramid engraving would start to wear out in the basic part of the top welding plate due to engraving the bottom welding plate 1 into the top workpiece 3.1.

This would consequently lead to disproportionate forms pyramid engravings which would result in a disproportionate weld since the top workpiece 3.1 would not get close enough to the bottom workpiece 3.2 in the area of the apex of the pyramid engraving which would be worn out.

The presented invention does not address the top welding plate 1 heating mode. However, it merely specifies guidelines regarding the importance of the temperature of the top welding plate 1 or the finishing layer 1.3 being as constant as possible.

The bottom welding plate 2 is made of steel and is not heated. The function of the bottom welding plate 2 is to convey the excess heat which has to be conveyed from the bottom workpiece 3.2 after the welding phase. The heat of the top workpiece 3.1 is transferred to the bottom workpiece 3.2, while the heat of the bottom workpiece 3.2 is conveyed to the bottom welding plate 2.

The method of guiding the top welding plate 1 towards the bottom welding plate 2 is particularly important and has to be carried out in a manner in which the surface pressure is Description evenly transferred from the top welding plate 1 via both workpieces 3.1 and 3.2 to the bottom welding plate 2.

The different geometry allocation between the pyramids ensures the transfer of pressure to the corresponding point along the thickness of the workpiece and the appropriate allocation of the pressure conditions so that workpiece 3.1 and workpiece 3.2 are welded along the entire envisaged welding surface.

This way, two options of guiding the top welding plate 1 towards the top welding plate 2 are available, namely:

1. whether by using precise and very parallel guides to achieve a completely complementary planes of welding plate 1 and 2;

2. or by clamping the top welding plate 1 via an elastic polymer or similar so that the top welding plate 1 is adjusted to the plane of the middle geometric profile of the bottom welding plate 2 during engraving into the workpiece 3.1.

The method described under item 1 does not take into account the thickness tolerance of both workpieces which strongly affects the resulting quality of the weld between the workpieces 3.1 and 3.2 and is a very expensive execution which, however, does not offer any advantage over the option described under item 2.

The method described under item 2 at the same time compensates for the thickness tolerances of workpiece 3.1 and workpiece 3.2 since it elastically adjusts to the welding surface of the bottom welding plate 2 and the surface pressure in the case of workpieces 3.1 and 3.2 of different thickness is also uneven along the entire welding surface.

According to the parallelism of the top welding plate 1 against the bottom welding plate, the guidance or clamping of both welding plates must be within the tolerance of +- 0.01 to 0.02 depending on the parallelism of the finishing layer 1.3 of the top welding plate against the finishing layer of the bottom welding plate 2.

The subject of the invention is also the selected method of guidance of the top welding plate 1 against the bottom welding plate 2 which can be carried out in the specific manner of the so- Description called elastic adjustment of the top welding plate 1 against the contour or the bottom welding plate 2.

This can be performed by clamping the top welding plate 1 into the machine welding guides via the elastic pads or the elastic base 5.

The elastic base 5 must connect the entire upper surface of the top welding plate 1 which is opposite and parallel surface to the finishing layer 1.3 of the top welding plate 1.

The function of the elastic base 5 of adjusting the parallel position of the top welding plate 1 according to the position of the bottom welding plate 1 when compressing the top welding plate via the workpiece 3.1 and workpiece 3.2 and finally onto the bottom welding plate 1.

With slight deviations from coaxiality which could result in the destruction of the finishing layer 1.3 of the top welding plate 1, the elastic base 5 has the function of adjusting the top welding plate 1 according to the axis of the bottom welding plate 2.

The elastic base 5 can be made of rubber or any other polymer with a suitable elasticity module which can be compared with the rubber elasticity module with a hardness ranging from 50 to 100 units on the Shore scale and rubber thickness ranging from 5 to 10 mm.

Claims

Claims Patent claims

1. The wear-resistant welding panel is characterized by the fact that it is a top

welding plate made of copper alloy of the following composition, namely Co=1.0%, Ni=1.0%, Be=0.5%, Fe=<0.2%, SI=<0.2%, Cu=the remainder.

2. According to the claim 1 the wear-resistant welding plate is characterized by the fact that the top welding plate (1) has on the bottom surface area (1.1) a constructed engraving in the form of pyramids. The dimension of the pyramids is determined in terms of the dimension of the pyramid apex (a) which ranges from 0.1 to 0.5 mm, pyramid interaxial section dimension (b) which ranges from 0.3 to 1.5 mm and the incline angle of the pyramids (alpha) which ranges from 90 to 160 degrees.

3. According to the claim 2 the wear-resistant welding plate is characterized by the fact that the surface (1.1) is treated with regard to the degree of roughness of N4 or finer.

4. According to the claims 1 and 3 the wear-resistant welding plate is characterized by the fact that it has an 8 to 15 micron thick NiP (nickel) layer (1.2) applied to the bottom basic surface (1.1) and a 1 to 5 micron thick finishing layer (1.3) made of CrN (chrome-nitride) is applied to the former layer (1.2).

5. According to the claims 1 and 4 the wear-resistant welding plate is characterized by the fact that the finishing layer (1.3) has a degree of smoothness of processing of N4 or finer.

6. According to the claim 4 the wear-resistant welding plate is characterized by the fact that the hardness of the finishing layer (1.3), the top welding plate (1) is of 60 Hrc or more. Claims

7. According to the claims 1 and 2 the wear-resistant welding plate is characterized by the fact that the thickness of the top welding plate (D) equals 10 mm or more.

8. According to the claims 1 and 4 the wear-resistant welding plate is characterized by the fact that its finish layer (1.3) is heated to the operating temperature ranging from 150 to 250 degrees Celsius.

9. According to claim 1, the wear-resistant welding plate is characterized by the fact that the top welding plate (1) can be clamped into the fixed welding machine guides with the guiding tolerance along the vertical axis of less than 0.05 mm and is guided towards the bottom welding plate (2).

10. According to the claims 1 and 9, the wear-resistant welding plate is characterized by the fact that the top welding plate (1) can be clamped into the fixed welding machine guides with the guiding tolerance along the axis parallel to the finishing surface (2.1) of the bottom welding plate (2) of less than 0.03 mm and is guided toward the bottom welding plate (2).

11. According to the claims 1, 9 and 10 the wear-resistant welding plate is

characterized by the fact that the top welding plate (1) can be clamped to an elastic base (5) with a thickness of 5 to 10 mm, a hardness of 50 to 100 Shore through which the welding machine guides it towards the bottom welding plate (2).

12. The wear-resistant welding plate is characterized by the fact that it performs the procedure of a vertical downward movement, whereby its finishing layer (1.3) is engraved into the top workpiece (3.1) whereby the heat from the finish layer (1.3) is transferred to the top workpiece (3.1) and then to the bottom workpiece (3.2) and causes melting through of both workpieces (3.1) and (3.2) or a contact weld without the addition of material.