EP0902100A1 - Thermospray method and apparatus for carrier body - Google Patents

Abstract

Method comprises: a) base element surface conditioning; b) separating agent applied to surface (8); c) spraying of surface with metal or self-flowing alloy; d) separation of sprayed layer (14) from base element. The base element has a support cylinder and extraction disk (19), with chamfers (23.1 and 23.2), producing necking in the sprayed layer (14).

Description

The invention relates to a thermal spray process for the production of Carrier bodies and a device for performing the method, wherein the obtained carrier body used in particular in the graphics industry can be.

DE 41 40 768 C2 discloses a method for producing an offset printing form a metallic material for a forme cylinder of a printing press. First becomes a plate on the circumference and width of the forme cylinder cut to size and with at least one end face Provide register facilities. Then the plate-shaped blank is opened for printing plate production conventional type coated and exposed, after which the rectangular plate in a welding device by bending into a Bring hollow cylinder shape and clamped there in register. The one on top of the other facing edges of the plate are seam welded together longitudinally, whereby the welding process is carried out in such a way that a weld seam is formed which is on the top and Bottom each has a concave shape. In addition to the coating and The resulting printing form can be exposed to the plate-shaped blank coated and exposed on the forme cylinder.

A disadvantage of this manufacturing process is the fact that the length is stretched of the plate-shaped blank, which will later give the diameter, exactly parallel and with a correspondingly high accuracy of significantly better than 1/10 mm tailored. It also causes the introduction of heat when welding a longitudinal distortion of the material in the weld area. This elongation leads to a ripple on both sides along the weld. When using a sleeve produced in this way leads to the inevitable waviness in the seam area to the fact that air pockets occur, which are under external pressure on the sleeve this migrate, which causes the sleeve to twist on the cylinder. This results in the need for an additional operation subsequent calibration of such sleeves made according to this procedure has been.

DE 39 08 999 C2 discloses a cylinder body and a method for coating of the cylindrical body. It is proposed to have a cylindrical body like this to be provided with a seamless coating that as a coating material thixotropic multi-component material in the form of a propellant and inhibitor staggered, flowing foam with rotation and feed on the cylindrical body is applied approximately in a spiral. As a sleeve material metallic aluminum or a carbon fiber reinforced plastic is used. The However, the use of plastic sleeves also has disadvantages. For example in view of the considerably lower modulus of elasticity, these have to be increased Wall thickness can be made to be comparable to metallic sleeves Achieve seat strength. High wall thicknesses, in turn, for example in the Application of functional layers of higher temperature to be treated are exposed to temperature, resulting in loss of Dimensional accuracy and build up high internal stresses.

From EP 0 421 145 A2 and EP 0 715 966 A1 are sleeve-shaped rubber blankets become known, which laterally on blanket cylinders from Have rotary printing presses installed. The rubber coating is on Nickel sleeves applied. The nickel sleeves are electroplated manufactured. A mother cylinder is inserted into the nickel bath a thin nickel skin, which later after reaching the required wall thickness is rolled from the master cylinder. The nickel sleeve production in this way has an increased power requirement and is extremely time consuming.

Thermal spray processes are used today to make the most diverse Components such as machine components, implants or structural components to coat a variety of materials. The one with the coating Spraying methods and spray additives are used to a high degree application-specific. Classic areas of application of thermal Spraying is the wear and corrosion protection, the repair coating as well as thermal or electrical insulation and often a combination of these Aims.

Aim of the conventional spraying technique mentioned to solve more demanding Coating tasks have so far been to ensure the best possible adhesion of the to obtain the generated layer on the component to be coated.

Based on the weaknesses and disadvantages of the status of the The technology and further development of the application of spray processes lies in the present invention the object of the graphic industry stiffness and strength-optimized base carrier sleeves for the production of Transfer carriers, printing forms, impression rollers and the like inexpensive for To make available.

The object is achieved by the features of claim 1 solved.

The advantages resulting from the solution according to the invention are more diverse Nature. In contrast to those previously produced using thermal spraying processes Layers are those produced according to the method of the invention Easy to remove layers from the body that only gives shape. Which ductile, elastic layer resulting from the spraying process is solid Material very similar and gives the body thus obtained an elasticity that its easy handling enables. The ductility of the body allows one Expanding the body for mounting on a cylinder of a graphic Machine; after switching off one necessary to expand the ductile body The body can be pressurized on the circumference using a press fit be held by a cylinder. It can be both Actuate transfer cylinder as well as a printing form cylinder on which the sleeve-shaped body produced according to the invention can be drawn up. Next Applications for the offset method are also the application of the invention preserving sleeve-shaped body in the gravure process conceivable.

In a further embodiment of the idea on which the invention is based, the metal or the metal alloy or the self-flowing alloy can be sprayed on in accordance with the flame spraying process. In addition to the flame spraying process, the arc spraying process can also be used, as can the high-speed flame spraying process. In addition to metals or metal alloys or a self-flowing alloy, the material to be sprayed on can be an oxide or also carbides or ceramic-metal mixtures (cermets). In order to prepare the outer surface of the shaping base body for the thermal spray layer to be produced, this must be conditioned, for which purpose a blasting process is used. By means of the blasting method, a roughness of the lateral surface is brought about, which is characterized in that the elevations determining the roughness have a round contour. The roughness of the outer surface of the shaping body is R _Z 25 µm. The material preferably used to produce the rough outer surface in the blasting process to be used is glass spheres. The prevailing pressure in the blasting process for spraying the glass balls is between 2.5 and 3.5 bar. In order to facilitate the detachment of the thermal spray layer produced according to the invention from the outer surface of the shaping base body, the conditioned outer surface of the shaping base body is provided with a layer of a release agent which is up to 5 μm thick. The release agent can be powdered graphite dust or silicone can also be used. It is also possible to use Teflon as a release agent. After the outer surface of the shaping base body has been pretreated in this way, the spray layer to be applied thermally is applied in a range between 0.1 and 0.6 mm thick.

The inventive device for performing the thermal Spraying process comprises a shaping body, which is a support cylinder as well as a pull-off disc, between the support cylinder and the Pull-off round a deflection bevel is formed, which is a constriction in the thermal applied spray layer generated. Between the support cylinder and the An extraction chamber is provided, which is equipped with a Pressure medium through the pull-off disc or through the support cylinder is pressurizable. An annular gap between the support cylinder and The pull-off blank is made up of an end face of the support cylinder and the pull-off blank limited. The annular gap opens below the necking point of the thermal sprayed material in the area of the deflection chamfer.

To improve the formation of an air gap and to make it easier to detach the thermally sprayed layer from the outer surface of the support cylinder achieve, both the support cylinder on the front side and the pull-off disc are on the front side provided with a taper.

Further details of the inventive method and the inventive Device can be found in the description and the attached figures become.

Figur 1

den schematisch dargestellten Aufbau einer Anlage zum thermischen Aufbringen einer Spritzschicht auf einen formgebenden Grundkörper,

Figur 2

einen Längsschnitt durch den formgebenden Grundkörper, bestehend aus Stützzylinder und Abziehronde,

Figur 3

eine auf dem formgebenden Grundkörper aufgebracht Spritzschicht mit ausgebildeter Einschnürstelle, jedoch noch nicht beaufschlagter Expansionskammer und

Figur 4

eine durch Beaufschlagung der Expansionskammer teilweise abgelöste thermische Spritzschicht.

It shows:

Figure 1

the schematically illustrated structure of a system for the thermal application of a spray layer on a shaping base body,

Figure 2

a longitudinal section through the shaping base body, consisting of a support cylinder and pull-off disc,

Figure 3

a spray layer applied to the shaping base body with a trained constriction point but not yet loaded expansion chamber and

Figure 4

a thermal spray layer partially detached by loading the expansion chamber.

In Figure 1 is an arrangement for performing the reproduced method according to the invention.

An order station 1 comprises one on a machine frame 2 in Recording tips 3 and 4 rotatably mounted base body, one Includes support cylinder 5 and a pull-off blank (see FIG. 2). The the is to be applied to the thermal spray coating which gives the shape of the base body the receiving tips 3 and 4 rotatably supported and can not by one here drive shown in detail can be set in rotation. The support cylinder 5 is by means of a cylinder pin 6 in the receiving tip 3, the The end face of the cylinder faces the receiving tip 3. Parallel to the axis of the Support cylinder 5, a carriage 9 is arranged, which in guides 10 on Machine frame can be moved in the feed direction 13. On the carriage 9 is a Spray head 11 arranged, the material to be sprayed on via a feed line 15 applies to the outer surface 8 of the base body. Depending on the feed rate and speed of the shaping base body spray layers 14 in Produce thickness range between 0.1 and 0.6mm, the spray layer very ductile and elastic is very similar to solid material. Such a way endless sleeves made of coherent material can be - how will be described in more detail below - from the scope of the Detach support cylinder 5.

FIG. 2 shows in longitudinal section one of a spray layer to be applied thermally the basic body.

The shaping base body shown in longitudinal section comprises a Support cylinder 5, on the end face 7 of which the cylinder journal 6 is located. Of the Support cylinder 5 has a cavity, the end faces and Shell surfaces 8 limited and penetrated by a guide rod 17. To one annular end face 27 of the support cylinder 5 is a corresponding annular end face 28 of a pull-off disc 19. The Pull-off disc 19, also penetrated by the guide rod 17 already mentioned, which is provided with a profile 18 is with a connection 20 for a Media equipped. The connection 20 for the pressure medium comprises one Channel 21, which is in an expansion chamber 22 between the support cylinder 5 and the Pull-off disc 19 opens. The expansion chamber 22 is shown in FIG Idle state 22.1 shown. The through the mentioned end faces 27, 28 of Support cylinder 5 or pull-off disc 19 formed joint 29 forms an annular gap extending around the cylinder axis into a deflection chamfer 23 at the transition of the support cylinder 5 to the extraction disc 19 opens. Both is on the cylinder side Deflection chamfer 23.1 is provided as well as a deflection chamfer 23.2 on the condenser side is provided, which in the abutting state of the support cylinder 5 and Pulling disc 19 form a continuous deflection chamfer 23, which leads to the formation of a Constriction 30 leads in the thermal spray layer 14.

For the sake of completeness, it should also be mentioned that the Pulling disc 19 on the guide rod 17 a nut 24 together with lock nut 25 as Stop are provided in order to pressurize the expansion chamber 22nd with a pressure medium the travel of the pull-off probe 19 relative to Limit support cylinder 5.

In the state shown in FIG. 2 - before applying a thermal spray layer - the surface of the support cylinder 5 is conditioned by means of a blasting process. Usually, blasting processes are used to roughen subsurface surfaces with the aim of optimal adhesion. This means making the surface as sharp as possible. However, in order to ensure that the spray layer 14 can be easily removed, the roughness must be brought about with edges that are as round as possible. The surface of the support cylinder 5 is therefore produced using a blasting method using glass balls of a defined size and a blasting pressure between 2.5 and 3.5 bar. The average roughness depth R _Z , which is generated by this method, is R _Z 25 µm.

After roughening the outer surface 8 of the support cylinder 5 according to the above Said, the jacket surface 8 conditioned in this way is provided with a release agent provided what is applied in a film up to 5 µm thick. The application a release agent, such as graphite, silicone or Teflon, acts one mechanical clawing of the striking at high speed Spray particles against the base of the base body and prevents Baking together with the outer surface 8 of the support cylinder 5. The applied Release agent supports the detachment of the spray layer 14 after it has cooled the outer surface 8 of the base body.

FIG. 3 shows a spray layer applied to the shaping base body shown with trained constriction 30.

The sprayed layer 14 is applied to the conditioned lateral surface 8 of the support cylinder 5 with a roughness depth of R _Z = 25 μm and provided with a separating agent, with the arrangement according to FIG. 3 while rotating the shaping base body and advancing the spray body 11. The expansion chamber 22 located between the support cylinder 5 and the pull-off disc 19 is in its idle state 22.1, ie not acted upon by a pressure medium. In the area of the deflection chamfer 23 formed by the two tapering areas 23.1 and 23.2 on the support cylinder 5 and pull-off disc 19, a constriction point 30 has formed in the spray layer 14. Before the spray layer 14 was applied, the outer surface of the removal disc 19 was not subjected to any surface conditioning, which is why its roughness is higher than that of the outer surface 8 of the support cylinder 5. This means that the part of the spray layer 14 which is applied to the pull-off disc 19 of the shaping base body opposes the detachment with a higher resistance. The expansion chamber 22, which is still in the idle state 22.1, is connected to the latter via the gap 29 defined by the contact area of the end face 27 or 28 of the support cylinder 5 or pull-off probe 19, which opens approximately centrally into the deflection chamfer 23.

FIG. 4 shows a part that has been detached due to the expansion chamber being acted upon coherent thermal spray coating.

The pull-off disc 19 is acted upon by a pressure medium, which via the Channel 21 acts on the expansion chamber 22. By building up Pressure in the expansion chamber 22 results in a surface pressure between the Support cylinder 5 and the pull-off disc 19, whereby the gap 29 between the End faces 27, 28 of the support cylinder 5 and pull-off 19 is widened. By the The gap 29 passes the pressure medium under the coherent sleeve-shaped Spray layer 14 and applied to the underside 14.2.

In order to avoid a sudden impact on the spray layer 14 beginning formation of the gap 29 by the pressure medium is carried out by the Deflection phase 23 generates an additional length in the form of a constriction 30.

When the pressure medium acts on it, this constriction point 30 is elongated, the spray layer 14 extends in the horizontal direction and allows the formation of a horizontal gap 26, whereby the printing medium the bottom 14.2 of Spray layer 14 can completely infiltrate and in this way a detachment the same caused by the outer surface 8 of the support cylinder 5.

In the state shown in FIG. 4, the area covering the support cylinder 5 is the spray layer 14 detached from the outer surface 8 of the support cylinder 5 while the part of the spray layer 14, which is located on the peel 19, because of the greater friction still adheres to the outer surface of the extraction disc 19.

The combination of nut 24 and lock nut 25 causes a restriction of the Travel of the pull-off disc 19 relative to the support cylinder 5 on the with Profiling 18 provided guide rod 17th

Sleeves produced in this way without a seam have a ductile elastic Behavior on and are in the manner described above according to the invention can be produced considerably more cost-effectively than those known from the prior art elaborately deposited on a master cylinder Nickel sleeves. The material thicknesses of the tubular bodies to be produced are adjustable between 0.1 and 0.6mm depending on feed and speed of the shaping basic body, in relation to the material discharge on Spray head 11. On sleeves made of injection molded with such wall thicknesses Metal or sprayed metal alloys can be used, for example, for that Apply the necessary transfer layers using offset processes or pressers for Manufacture gravure applications. It is also used as a sleeve Printing form in printing machines possible to use instead of finite Printing plates.

Reference list

1

Order station

2nd

Machine frame

3rd

Recording peak

4th

Recording peak

5

Support cylinder

6

Cylinder journal

7

Cylinder face

8th

Cylinder surface

9

carriage

10th

guide

11

Spray head

12th

Order direction

13

Feed direction

14

Spray coating

14.1

Top side spray coating

14.2

Underside of spray coating

15

Supply

16

Cylinder axis

17th

Guide rod

18th

thread

19th

Pull-off disc

20th

Compressed air connection

21

channel

22

Air chamber

22.1

Hibernation

22.2

expanded state

23

Deflection bevel

23.1

Deflection chamfer on the cylinder side

23.2

Deflection chamfer on the condenser side

24th

mother

25th

Lock nut

26

Air gap

27

End face on the cylinder side

28

End face on the condenser side

29

gap

30th

Constriction

Claims (25)

Process for producing thermally sprayed endless layers with the following process steps: Surface conditioning of the shaping base body (5) with edges that are as round as possible, Applying a release agent to the surface (8) of the base body (5) conditioned in this way, Spraying a metal / a metal alloy or a self-flowing alloy onto the conditioned surface (8) of the base body (5) while rotating the same and advancing a spray head (11), Detaching the spray layer (14) obtained from the shaping base body (5). Method according to claim 1,
characterized,
that the material is sprayed according to the flame spraying process. Method according to claim 1,
characterized,
that the material is sprayed on in accordance with the arc spraying method. Method according to claim 1,
characterized,
that the material is sprayed according to the high speed flame spraying process. Method according to claim 1,
characterized,
that the spraying of the material is carried out according to the plasma spraying process. Method according to one of claims 2 to 5,
characterized,
that the material to be sprayed on is oxides. Method according to one of claims 2 to 5,
characterized,
that the material to be sprayed on is carbide. Method according to one of claims 2 to 5,
characterized,
that the material to be sprayed on is ceramic-metal mixtures. Method according to claim 1,
characterized,
that the jacket surface (8) of the base body (5) is conditioned by means of a blasting process. Method according to claim 9,
characterized,
that the roughness of the lateral surface (8) of the base body (5) R _{Z is} 25 µm. Method according to claim 9,
characterized,
that the blasting of the outer surface (8) of the base body (5) takes place with glass balls. Method according to claim 9,
characterized,
that the blasting pressure of the blasting process is between 2.5 and 3.5 bar. Method according to claim 1,
characterized,
that the conditioned outer surface (8) of the base body (5) is provided with a layer of a release agent up to 5 µm thick. A method according to claim 13,
characterized,
that the release agent is graphite. A method according to claim 13,
characterized,
that the release agent is silicone. Process according to claim 13,
characterized,
that the release agent is Teflon. Method according to claim 1,
characterized,
that the thickness of the spray layer (14) is in the range between 0.1 and 0.6 mm. Device for carrying out the method according to claim 1,
characterized,
that the shaping base body comprises a support cylinder (5) and a pull-off disc (19), between which a deflection chamfer (23) is formed, which creates a constriction point (30) in the thermally applied spray layer (14). Device according to claim 18,
characterized,
that the support cylinder (5) and the pull-off disc (19) can be moved relative to one another. Device according to claim 18,
characterized,
that there is an expansion chamber (22) between the support cylinder (5) and the pull-off disc (19). Device according to claim 18,
characterized,
that an annular gap (29) is delimited by an end face (27) on the cylinder side and an end face (28) on the condenser side. Device according to claim 18,
characterized,
that the annular gap (29) opens into the deflection chamfer (23) below the constriction point (30) of the thermally sprayed layer (14). Device according to claim 18,
characterized,
that the support cylinder (5) has a deflection chamfer (23.1) on the end face. Device according to claim 18,
characterized,
that the pull-off disc (19) has a deflection chamfer (23.2) on the end face. Endless sleeve-shaped body made of thermally sprayed material with a Material thickness between 0.1 and 0.6mm for mounting on cylinders in Rotary printing machines.

Images