DE10324404A1 - Forming process for dental teeth uses a press with controlled heating while controlled pressure is applied - Google Patents

Abstract

The unit has an upper heating chamber (1) with insulation blocks (3,4) and heating coil (11). The forming tool for the dental tooth object (15) is located on a table (20) that is inserted through a bottom opening (5). The table is mounted on a spindle (41) that is raised and lowered by an electric motor (26). A defined pressure and temperature is applied with timing control.

Description

The The present invention relates to a method for producing Objects for dental prosthesis or partial prosthesis, in which a dental mass heated and is pressed into a mold and in which a certain pressing time is specified.

Furthermore The present invention relates to a press furnace for performing a such procedure.

at Methods of the type mentioned at the outset are usually described in so-called Mold inserts arranged in muffles used the one you want Have object corresponding shape space. The mold space follows a prepress chamber into which a piston is inserted after the manufacture of the object needed dental mass was placed in the pre-compression chamber. By the effect of heat the mass is melted and then pressed through the piston into the mold space.

The The mold insert is produced, for example, as in FIG DE-PS 664 133 or AT-PS 157 210, the disclosure of which by reference is included in the present application.

Important in the manufacture of dental prosthetic items using such a method is that the dental prosthetic items completely fill the mold space. at The production is therefore given a pressing time Conditions met in every case. The is called, the actually required pressing time becomes a safety time slammed that is chosen so large that the conditions mentioned are fulfilled with certainty. This increases the manufacturing time is not negligible, which also affects the manufacturing costs effect.

The The invention has for its object a method of the beginning to improve the type mentioned. In particular, the manufacturing time and the manufacturing cost can be reduced. In addition, an improved Press furnace to carry out of such a procedure.

The The first-mentioned task is solved in that the predetermined pressing time while depending on the pressing from while values of process and / or Object parameters such as temperature, time, negative pressure and / or pressing force changed becomes.

By Determination of the values of process and / or object parameters can shed light on this how far the dental technical mass of the mold space are obtained filled out and how far it has hardened is. Is the filling completely or largely complete, the pressing time can be shortened according to the invention. So that the total manufacturing time across from conventional processes shortened become. Moreover the manufacturing costs are also lower as a result.

The Change, in particular shortening the According to an embodiment of the invention, pressing time is dependent from that exercised by the pressed material Counterforce. change If the opposing force does not change, it can be concluded that the molding space is at least approximately filled by the mass.

A change the counterforce is preferably determined according to the invention by that the regulation of the pressing force is monitored. Takes place over one no readjustment for a certain period of time, it can be concluded from this that the counterforce has not changed.

Next a shortening the press time when the behavior of the pressed material is determined to be constant during the Pressing can also be an extension of the Press time takes place if based on the process and / or object parameters it is determined that the molding space has not yet been filled by the mass. In order to can advantageously be avoided that the method to ended early and not optimal quality is obtained.

The shortening or extension the pressing time takes place according to a design around a certain one Amount. However, it is preferred if the extension or shortening by a certain percentage, preferably based on the remaining one Pressing time. It can be easily programmed a sharp shortening the pressing time can be achieved.

A percentage reduction or extension is particularly advantageous if, according to a further embodiment the invention with continued appropriate behavior of the pressed material or more shortenings or extensions the press time. Too much shortening or extension can be avoided.

The further extensions or shortenings can take place to different degrees or after a different period of time than the first or the previous shortening or ver lengthening. The change in the pressing time can thus be further optimized.

To A further embodiment of the invention can be used to check the Process and / or object parameters during pressing and a change the pressing time only after a basic pressing time. In order to prevents a shortening to early and ensures that a minimum pressing time is observed becomes.

The change the pressing time can basically done manually become. However, an automatic change is preferred. This can simplify production.

Prefers the size of the change is adjustable. This allows you to flexibly respond to the different requirements different press material to be reacted.

As well the time and / or the period of the checking of the Process and / or object parameters adjustable. That is one too Adaptation possible.

Finally is also prefers length the basic pressing time, which is also set to zero or not programmed, so it can be omitted.

For the procedural and / or object parameters, a tolerance range can preferably be specified. Change the process and / or object parameters only within the Tolerance range, this is interpreted as unchanged behavior. This can prevent minor fluctuations in the process and / or object parameters an actually meaningful shortening of the Prevent pressing time or an unreasonable extension the same.

Quality Results can Moreover then be achieved when the start of the pressing time on reaching the target pressing force is determined.

The second task is solved by a press furnace, characterized by a combustion chamber for Inclusion of a particularly arranged in a so-called muffle Mold insert with one of the desired Object corresponding mold space and one connected to the mold space Prepress chamber, in which a press piston can be used for sealing, a heater for heating the combustion chamber, a drive device for actuating the Press piston and a control device for controlling the press furnace, which is programmed so that the specified pressing time during the Pressing depending the determined process and / or object parameters are changed.

Prefers it is when the control of the press furnace according to the invention is freely programmable. This allows the pressing process to be set individually.

To A special embodiment of the invention can be the drive device for actuation be formed by two or more plungers. This can advantageously several objects can be produced and treated at the same time.

Likewise It is advantageous if means for flooding the combustion chamber Air or gas, especially outside air, are provided while maintaining the pressing pressure. in this connection can in particular be an inlet and an outlet valve, with an existing vacuum connection as outlet valve can serve to evacuate the combustion chamber. Through the means flooding and thus rapid cooling of the combustion chamber too without opening enables them so that the press pressure can be maintained during flooding.

To The combustion chamber has a particularly preferred embodiment an opening on the bottom on, and is a burn table over this opening retractable and extendable into the combustion chamber, the one opposite the opening Wall of the combustion chamber designed as a stop for the plunger is. Such an embodiment enables advantageous pressing, where the pressing chamber is not from above but from below is loaded.

A Such a preferred embodiment allows the combustion chamber to be constructed of the press furnace analogous to the construction of a kiln without a press device. It contains neither moving parts nor additional Refrigerate. This ensures this configuration also particularly the possibility of producing Dentures that are not pressed but only fired without adaptations to the normal firing process and without loss of firing results.

As It has proven particularly advantageous if the firing table is carried by a liftable and lowerable lift bar, which in one Lift tube slidably guided is, in turn, a lift plate with a passage opening for the lift rod wearing, a friction seal is provided between the lift rod and lift tube is through which the lift tube with the lift plate when lifting and Lowering is carried along, and with the lift plate in its raised position Position seals the combustion chamber.

In order to can be a particularly skillful and inexpensive construction of the press furnace can be achieved.

To In a further embodiment of the invention, means are provided through which the mass of an object arranged on the firing table can be determined is, as well as means by which the firing temperature, the pressing force and / or the treatment time can be adapted to the object mass. Through this measure can the quality of manufactured objects can be further improved because of the mass of the object is known exactly. Determining the mass can doing directly over The movement of the burning table is done by moving the burning table required forces measured and compared with and without firing material.

To a further embodiment of the press furnace according to the invention, which also claims for itself the drive device comprises a flexible tensile force transmission element, like chain or strap, which is fixed with one end and with its other end can be wound up and unwound on a drum or disc is attached and in between via a tensile force transmission element by preferably deflecting about 180 ° Deflection device is running, which with an actuator for direct or indirect displacement of the plunger is. Through the deflection device, the actuating device when winding of the tensile force transmission element depending on the arrangement raised or lowered. This can advantageously a movement of the plunger can be performed.

By a second, at about height the fixed end of the tensile force transmission element Deflection device can achieve a maximum stroke of the firing table become.

The first deflection device is in particular with the firing table carrying lift rod connected. The firing table can thereby of the tensile force transmission element can be raised and lowered to an object in the desired position Way to press.

Around To enable regulation of the pressing force can be between the End of the traction element and a force measuring device can be arranged in the press furnace.

embodiments the invention are illustrated in the drawing and are described below. They show, each in a schematic representation,

1 FIG. 2 shows a partially vertical front view of a press furnace according to the invention in a first position,

2 a representation according to 1 in a second position and

3 a representation according to 1 in a third position.

The press furnace shown comprises a combustion chamber housing 1 in which a combustion chamber 2 is trained. The combustion chamber 2 is from side insulating stones 3 and insulating capstones 4a and 4b surround. The combustion chamber points to the bottom 2 an opening 5 on.

The insulating stones 3 . 4a and 4b are in a pot 6 , for example made of aluminum, which is in the region of the opening 5 the combustion chamber 2 a corresponding recess 7 having. The top of the pot 6 is with a lid 8th locked. The housing 1 which, for example, also consists of aluminum, surrounds the pot 6 leaving a room free 9 that is over a crack 10 communicates with the environment.

In the combustion chamber 2 is also a radiator 11 arranged, which is designed as a heating coil and on the inside of the side insulating blocks 3 is arranged. The two capstones arranged one above the other 4a and 4b are each in paragraphs 12 . 13 of the lateral insulating stones 3 used. The lower insulating stone 4b has a central passage opening 14 on whose size is chosen so that a muffle 15 into the recess 14 can drive in. This passage opening is from the top 14 that with a corresponding paragraph 16 is provided, a pressure plate 17 , in particular made of high-strength ceramic. The pressure plate 17 also engages in a corresponding recess 18 in the bottom of the upper insulating brick 4a ,

The side insulating stones 3 in the combustion chamber 2 are also below the radiator 11 with an inner waistband 19 Mistake. This serves as a stop for a burning table 20 which is a substantially cylindrical central body 21 and an outer waistband 22 having. The dimensions of the central body 21 are chosen so that this between the inner waistband 19 of the lateral insulating stones 3 fits through, and the dimensions of the outer waistband 22 so that the burn table 20 overall in the opening 5 the combustion chamber 2 can drive in. The burning table 20 can therefore, as in 3 shown so far into the combustion chamber 2 retract that his outer waistband 22 on the inner waistband 19 of the lateral insulating stones 3 strikes.

The height of the burning table 20 is also chosen so that one on the firing table 20 arranged muffle 15 when retracting the firing table 20 into the combustion chamber 2 , into the recess 14 in the lower capstone 4b drives in, and also like this, that a muffle in the pre-pressing room, not shown here 15 inserted plunger 15 ' on the pressure plate 17 stops and by raising the firing table 20 can be pressed so far into the pre-compression space that the dental mass for producing the dental prosthesis or partial prosthesis is completely in the mold space of the muffle, also not shown 15 is pressed.

For moving the firing table up and down 20 is a drive device 23 provided in another housing 24 is arranged, which is also via a column 25 the combustion chamber housing 1 wearing. The drive device 23 includes a drive motor 26 who has a ring gear 27 drives on which a drive chain 28 can be wound up. The other end 29 the drive chain 28 is with one end 30 a bolt 31 connected, at the other end 32 a compression spring 33 supports on the one hand. On the other hand, the compression spring is supported 33 on a spring plate 34 starting with a central implementation 35 is provided, through which the bolt 31 is passed through. The spring plate 34 is in the middle upper area of the case 24 attached.

Starting from the bolt 31 is the drive chain 28 first down, then via a first deflection device 36 with two deflection rollers each effecting a deflection by approximately 90 ° 37 and 38 and then led up again. For example in the area of connecting the end 29 the drive chain 28 on the bolt 31 the drive chain is then around a second deflection device 39 with a single pulley 40 led, which also causes a deflection of about 90 °. The drive chain runs from there 28 on the ring gear 27 , The second deflection device 39 is also in the housing 24 attached.

The first deflection device 36 is not with the case 24 but with a lift bar 41 connected, which is a central upper opening 42 in the housing 24 reaches through and with its upper end the firing table 20 wearing.

The lift bar 41 is from a lift pipe 43 surround that also the upper central opening 42 in the housing 24 reaches through and a lift plate 44 wearing. The lift plate 44 has a central opening 45 through which the lift bar 41 is passed through. On the top of its edge is the lift plate 44 also with a seal designed in particular as an O-ring 46 Mistake.

Both at the upper end and at the lower end is between the lift bar 41 and the lift tube 43 one sliding guide each 47 . 48 for the lift bar 41 intended. It is also above the lower sliding guide 48 between lift bar 41 and lift tube 43 a friction seal 49 arranged.

The lift bar 41 and the lift tube 43 are furthermore by a cylindrical pipe socket 50 passed through on the top of the case 24 is provided and as a lower stop for the lift plate 44 serves. Between the lift tube 43 and the pipe socket 50 is a sliding tube in these 51 used, which extends into the housing 24 protrudes and serves as a lift guide. Finally, in the case 24 another force measuring device 52 arranged.

The operation of the press furnace shown is as follows:
In the in 1 shown position of the burning table 20 becomes a muffle on this 15 arranged with a mold insert for the tooth replacement or part replacement to be produced. In the pre-press room of the muffle 15 the dental material for the dental prosthesis or partial prosthesis, in particular as a pellet, is inserted, and then a plunger is inserted into the pre-compression chamber 15 ' used.

Now the drive motor 26 actuated in the sense that the drive chain 28 on the ring gear 27 is wound up. Because of the definition of the other end 29 the drive device 28 becomes the first deflection device 36 together with the lift bar 41 raised, and due to the friction seal 49 becomes the lift tube 43 with lift plate 44 taken away, the lift tube 43 through the sliding tube 51 to be led. This movement continues until the lift plate 44 outside of the housing 1 the combustion chamber 2 fits tightly. This position is in 2 shown.

Now the combustion chamber 2 about the heater 11 heated to the desired temperature until the dental material in the muffle 15 has melted sufficiently, and possibly the combustion chamber 2 evacuated. Then the drive motor 26 actuated again in the sense that the drive chain on the sprocket 27 is wound up. This further winding up the drive chain 28 becomes the lift bar 41 together with the first deflection device 36 raised further. Due to the lifting plate striking 44 outside of the combustion chamber housing 1 this remains in its position, and the lift rod 41 now moves out of the lift tube accordingly 43 out. In doing so, the lift rod 41 from the guides 47 and 48 guided.

By further lifting the lift bar 41 the firing table moves 20 with the muffle 15 further into the combustion chamber 2 one until the muffle 15 in the implementation 14 of the lower capstone 4b attacks. Raising the lift bar 41 with the burn table 20 will continue until the plunger 15 ' at the top of the pressure plate 17 strikes and into the muffle 15 is pushed in. This position is in 3 shown.

The indentation depth is determined with the help of the force measuring device 52 so determined that a desired pressing force of the plunger 15 ' is obtained on the dental material. The press force of the plunger 15 ' the technical force corresponds to the tensile force of the drive chain 28 on the bolt 31 which is the force of the compression spring 33 counteracts.

The Lift control and heating the combustion chamber is preferably carried out automatically after a previously entered one Burning program. Therefor is a controller, not shown here, and an associated one Input device provided. The burning program contains also a definable pressing time for pressing the dental material with a desired one Pressing force, which can be between 50 N and 380 N, for example. The control of the lift movement can be done with a two-digit lift command take place from the position of the lift plate L0 to L9 and a press force command P0 to P9 and then the shape L0 to L99. L90 to L99 correspond to the different press forces between the values from 50 N to 380 N. L90 means: top Position of the lift plate, press force 0 and L99: top position of the Lift plates, maximum pressing force (380 N).

About the position of the burning table 20 the pressing force is regulated to the desired value. Falls over the force measuring device 52 determined pressing force, so the firing table 20 If the pressing force is too high, the firing table will be raised 20 lowered.

The The specified pressing time is shortened according to the invention, if using the pressing force control it is determined that the behavior of the pressed material is not more changes. That is, the pressing time is shortened, for example, if the pressing force exceeds one Period of 35 seconds remains constant. The pressing time can then be reduced by a certain amount or a certain percentage, for example by 10% or by 50%.

it connect can other examination periods of for example 1 second each. The press force remains above this other review periods as well constant, the pressing time is reduced further, for example by same percentage based on the remaining pressing time. The pressing time is preferred by integer seconds shortened.

A after a first review period Press time of 35 seconds remaining, for example 100 seconds is, for example, by 10% to 90 seconds and after expiration a second review period from 1 second by a further 10%, i.e. rounded up by 9 seconds Shortened 81 seconds and so on.

The Pressing times is also preferably done automatically after a previously entered Program. This can have the form Txxxxx.PTA, for example, where T for Temperature and PTA stands for "press time automatic". The PTA command can be, for example, single-digit and mean units of 10% reduction in pressing time. So would have the command "T400.1" means that the maximum pressing time is 400 seconds and is reduced by 10%, if the pressing force does not change. On Command "T400.5" would mean that the maximum pressing time is 400 seconds and is reduced by 50% in each case, if the pressing force does not change.

It is possible, too, additionally to the shortenable Press time not shortened Basic press time. A program command could do this, for example, as follows look like: "T400 T400.9". This would mean that first the pressing force unchanged for 400 Seconds and that the subsequent pressing time of 400 seconds is also shortened by 90% if the pressing force changes does not change in the specified measuring interval.

Just like a reduction in press time can also extend the pressing time be provided. This could in particular if the pressing force is against Does not remain constant at the end of a basic pressing time. Instead of the specified Values can Of course other values can also be used. In addition, instead of one percentage reduction or extension also a reduction or extension in amount be provided.

The programming described is free programming and enables great flexibility. Basically, other types of programming can also be used. Furthermore, the mass of the object to be treated can also be placed on the firing table 20 are measured and the firing parameters, in particular the firing temperature and the pressing force, are adapted to this. Furthermore, the combustion chamber can be equipped with active cooling. For this purpose, for example, in addition to the usually existing exhaust valve for generating a negative pressure in the combustion chamber 2 an inlet valve for outside air or another gas may be provided. This allows rapid combustion chamber cooling 2 can also be achieved while maintaining the pressing pressure, i.e. with the combustion chamber closed. Finally, muffles with several plungers or several muffles can also be arranged on the firing table in order to produce several dental prostheses at the same time.

After the pressing process is finished, the firing table is opened 20 shut down again by the drive motor 26 is operated in the opposite sense as before. The drive chain 28 is thereby from the ring gear 27 unwound and the lift rod 41 presses the first deflection device 36 down until the lift plate 44 on the cylinder 50 seated. Now the muffle 15 from the burning table 20 removed and the manufactured object from the muffle 15 be removed. For rapid cooling of the combustion chamber 2 can do this before, but also during the lowering of the firing table 20 flooded with outside air.

1

combustion chamber housing

2

combustion chamber

3

Insulating

4a

upper capstone

4b

lower capstone

5

combustion chamber opening

6

pot

7

recess

8th

pot lid

9

free space

10

gap

11

heater

12

step

13

step

14

execution

15

muffle

15 '

plunger

16

step

17

printing plate

18

recess

19

inner collar

20

firing table

21

central body

22

outer collar

23

driving means

24

casing

25

pillar

26

drive motor

27

sprocket

28

drive chain

29

End of 28

30

End of 31

31

bolt

32

End of 31

33

compression spring

34

spring plate

35

Opening in 34

36

first deflecting

37

idler pulley

38

idler pulley

39

second deflecting

40

idler pulley

41

lift rod

42

Opening in 24

43

lift pipe

44

lift plate

45

Recess in 44

46

O-ring seal

47

slide

48

slide

49

friction seal

50

pipe socket

51

guide tube

52

Force measuring device

Claims (29)

Method for producing objects for tooth replacement or part replacement, in which a dental material is heated and pressed into a mold and in which a specific pressing time is specified, characterized in that the specified pressing time during the pressing as a function of values determined during the pressing process is changed by process and / or object parameters. A method according to claim 1, characterized in that the press time is dependent from that exercised by the pressed material Counterforce is changed. A method according to claim 1 or 2, characterized in that that the press time is dependent on the required regulation of the pressing force is changed. Method according to one of the preceding claims, characterized characterized that the pressing time when unchanged Behavior of the pressed material during of pressing over shortened a set period of time becomes. Method according to one of claims 1 to 3, characterized in that that the pressing time is determined when the changing behavior of the pressed material during the Pressing, especially towards the end of the pressing period, is extended. A method according to claim 4 or 5, characterized in that that extension or shortening by a certain amount. A method according to claim 4 or 5, characterized in that that extension or shortening by a certain percentage, especially based on the still press time that has not expired. Method according to one of the preceding claims, characterized characterized that continued appropriate behavior of the pressed material one or more further shortenings or extensions the press time. A method according to claim 8, characterized in that the further reductions or extensions to different degrees and / or after a different period than that first or previous shortening or extension. Method according to one of the preceding claims, characterized characterized that a review of the Behavior and / or a change in Pressing time only takes place after a basic pressing time has expired. Method according to one of the preceding claims, characterized characterized that change the pressing time is done manually. Method according to one of the preceding claims, characterized characterized that change the press time takes place automatically. A method according to claim 12, characterized in that the size of the change is adjustable. A method according to claim 12 or 13, characterized in that the time and / or the period of review of the behavior of the pressed material and / or the time of the change in Pressing time is adjustable. Method according to one of claims 12 to 14, characterized in that the length the basic pressing time is adjustable. Method according to one of the preceding claims, characterized characterized that for the tolerance of the material to be pressed is predetermined. Method according to one of the preceding claims, characterized characterized that reaching the start of the pressing time the target pressing force is determined. Press furnace for carrying out the method according to claim 1, characterized by a combustion chamber for receiving a muffle, in particular in a so-called 15 ) arranged mold insert with a mold space corresponding to the desired object and a pre-press space connected to the mold space, in which a press piston ( 15 ' ) can be used sealingly, a heating device ( 11 ) for heating the combustion chamber ( 2 ), a drive device ( 23 ) to actuate the plunger ( 15 ' ) and a control device for controlling the press furnace, which is programmed in such a way that the specified press time is changed during the pressing depending on the determined course of the pressing process. Press furnace according to claim 18, characterized in that the control is freely programmable. Press furnace according to claim 18 or 19, characterized in that the drive device ( 23 ) to operate two or more plungers ( 15 ' ) is trained at the same time. Press furnace according to one of claims 18 to 20, characterized in that means for flooding the combustion chamber ( 2 ) with air or gas, especially outside air, while maintaining the pressing force. Press furnace according to one of claims 18 to 21, characterized in that the combustion chamber ( 2 ) an opening on the bottom ( 5 ) has a burning table ( 20 ) through this opening ( 5 ) into the combustion chamber ( 2 ) is retractable and extendable and that the opening ( 5 ) opposite wall ( 17 ) the combustion chamber ( 2 ) as a stop for the plunger ( 15 ' ) is trained. Press furnace according to claim 22, characterized in that the firing table ( 20 ) from a liftable and lowerable lift bar ( 41 ) which is carried in an elevator tube ( 43 ) is slidably guided, which in turn has a passage opening ( 45 ) for the lift bar ( 41 ) elevator plate ( 44 ), whereby between the lift rod ( 41 ) and lift tube ( 43 ) a friction seal ( 49 ) is provided, through which the lift tube ( 43 ) with the lift plate ( 41 ) when lifting and lowering, and the lift plate ( 44 ) the combustion chamber in its raised position ( 2 ) seals. Press furnace according to one of claims 21 to 23, characterized in that means are provided by which the mass of a on the firing table ( 20 ) arranged object can be determined, and means by which the firing temperature, the internal combustion power and / or the treatment time can be adapted to the object mass. Press furnace for heating and pressing objects for tooth replacement or part replacement with a combustion chamber ( 2 ) to accommodate a particularly in a so-called muffle ( 15 ) arranged mold insert with a mold space corresponding to the desired object and a pre-press space connected to the mold space, in which a press piston ( 15 ' ) can be used sealingly, a heating device ( 11 ) for heating the combustion chamber ( 2 ), a drive device ( 23 ) to actuate the plunger ( 15 ' ) and a control device for controlling the press furnace, in particular according to one of claims 18 to 24, characterized in that the drive device ( 23 ) a flexible traction transmission element ( 28 ) like chain or strap that has one end ( 29 ) fixed and with its other end can be wound up and unwound on a drum or disc ( 27 ) is attached and in between via a tensile force transmission element ( 28 ) by preferably about 180 ° deflecting deflection device ( 36 ) running with an actuator ( 41 ) for direct or indirect displacement of the plunger ( 15 ' ) connected is. Press furnace according to claim 25, characterized in that the tensile force transmission element ( 28 ) about another, approximately at the level of its specified end ( 29 ) arranged deflection device ( 39 ) that runs between the first deflection device ( 36 ) and the drum or disc ( 27 ) is arranged. Press furnace according to claim 25 or 26, characterized in that the first deflection device ( 36 with which the firing table ( 20 ) carrying lift bar ( 41 ) connected is. Press furnace according to one of claims 25 to 27, characterized in that between the end ( 29 ) of the tensile force transmission element ( 28 ) and the press furnace a force measuring device ( 52 ) is arranged. Press furnace according to claim 28, characterized in that the one end ( 29 ) of the tensile force transmission element ( 28 ) in particular as a compression spring ( 33 ) trained spring is fixed, which is supported on the other hand on the press furnace.