RU2740469C1 - Dental complex for creation of dental prostheses - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to high-precision mechanisms in dentistry and is intended for making dental prosthetic, dental structures and prosthetic repair elements on dental implants by subtractive method. Dental complex comprises a bed, a working chamber, a denture prosthetic block attachment unit, a kinematic unit, a cartridge for instruments, a cartridge for dental prostheses; air pump, compressor, pump for supply of cooling liquid, electric pump, hydraulic tank, control system, electronic computing unit. Hydraulic tank is equipped with tray. Air pump is configured to remove contaminants from parts of the system and to dry the working chamber, the compressor is configured to cool the tool, pneumatic change of tool and removal of treatment products of dental prostheses, electric pump is made with possibility of detergent supply. Denture-prosthetic billet fixation unit is equipped with a cartridge for instruments. Control system is configured to determine the location of each axis and is provided with absolute encoders. Said kinematic unit incorporates axle rotation control mechanism. Cartridge for dental prostheses is made in the form of a rotary drum, and the cartridge for tools is made with possibility of arrangement of 2 to 20 cutters.

EFFECT: higher efficiency, reliability, wear resistance of complex elements and accuracy of making dental prosthetic dental structures.

1 cl, 7 dwg

Description

Technology area

The invention relates to high-precision mechanisms in the field of dentistry, intended for the manufacture of subtractive method of shaping denture, dental structures and prosthetic elements on dental implants, obtained as a result of five-axis finishing wet and dry processing of complex in shape and purpose parts from materials traditionally used in dentistry (PMMA, zirconium dioxide, clasp and casting wax), as well as titanium blanks (premills), lithium disilicate up to 100 mm in size and can be used directly in dental offices.

State of the art

From the prior art, the design of a dental milling machine (patent ES2765653T3, publication date 06/10/2020) is known, which contains an inlet ventilation hole and an outlet that are opposite to each other with respect to the milling space, made with the possibility of creating an air flow. Has a processing area, where one side, milling the space, has opening doors. The lower wall of the milling space is at least partially inclined and rounded, the lower wall below the machining zone being closed and having a constant slope.

The prior art knows the design of a five-axis milling machine with wet and dry milling modes (patent US20190381583A1, publication date 12/19/2019), which is selected as the closest analogue of the present invention. The milling machine contains a bed, consisting of a lower and an upper part, connected by vertical uprights-walls, a carriage with vertical movement along the Υ axis guides and longitudinal movement along the Ζ axis guides, a beam mounted on the X-axis guides in the upper part of the bed, on which a two-axis a pivoting device for fastening a workpiece, a workpiece storage fixed on a vertical rack-wall of the bed with an auxiliary rotating axis, which provides automatic change of workpieces in a two-axis rotary mechanism, and a tool cartridge having a longitudinal auxiliary axis, which allows automatic change of cutters during workpiece processing.

The disadvantages of these analogs are the low protection of the mechanisms of the main axes, drive guides and the cartridge for tools from the ingress of abrasive dust, the absence of forced removal of processing products, the inaccessibility of the machine mechanisms for organizing cleaning, insufficient reliability of the pneumatic clamping of the workpiece, the presence of test passes of the machine after each processing cycle, and also the large dimensions of the machine and its high cost.

Disclosure of the essence of the invention

The objective of the invention is to create a high-precision multifunctional dental complex that does not have the above disadvantages and allows for high accuracy of manufacturing prostheses - up to 5 microns and the dynamics of five-axis processing of workpieces, excluding additional diagnostics of the alignment of the complex during operation, to achieve minimum dimensions of the dental complex with maximum functionality, uniform distribution cutting forces, with the possibility of dry and wet work, a system for separating and cleaning the lubricating-cooling liquid, organize sealed automatic storage of tools and workpieces, with the possibility of their automatic replacement, as well as monitoring tool wear or breakage during operation, form a convenient working chamber for processing with easily washable, anti-corrosion and wear-resistant coating, to realize a large interoperative resource, as well as simple maintenance and quick repair of the dental complex, equip a hundred a matological complex with forced flushing, blowing and cleaning of the working chamber parts, maximum noise isolation, a built-in control computer with a convenient touchscreen for the implementation of a fully automated process for the manufacture of high-precision, complex in shape and purpose dentures, dental structures and prosthetic elements directly in dental clinics (offices).

The technical result consists in creating an invention that allows:

- simultaneously produce several dental prosthetics independently of each other;

- to increase the number of simultaneously manufactured dental prosthetics;

- to increase the reliability and durability of the elements of the dental complex.

- to automate, with high accuracy, the process of manufacturing denture dental structures that are complex in shape, material and purpose.

The dental complex consists of:

- hulls;

- a monolithic rigid bed with a high degree of vibration absorption and noise insulation;

- a kinematic unit equipped with a mechanism for controlling the rotation of the axes, consisting of five orthogonal axes spaced along the carriages;

- spindle carriages with linear axes Υ and Z;

- carriages of the block for fastening the workpiece with a linear axis X and rotary axes A and B;

- high-precision guides of the main linear axes;

- control systems for determining the location of each axis;

- temperature sensors;

- controllers for software self-diagnostics of axle drives by current consumption;

- controllers for absolute software maintenance of the degree of wear of cutters;

- compressor;

- centrifugal pump for supplying cutting fluid;

- centrifugal air pump;

- working chamber;

- an electric pump for supplying detergent;

- a hydraulic tank with filters equipped with a sump;

- block for fixing denture blanks

- cartridge for denture blanks;

- a workpiece fixing mechanism equipped with a thrust thread and containing an electric drive;

- an electronic computing unit equipped with a remote touch monitor.

Also, to improve the accuracy of the complex, temperature sensors were used for software compensation of thermal expansion of the complex parts, preventing inaccuracies in processing. Controllers are used for software self-diagnostics of axle drives by current consumption, as well as controllers for absolute software tracking of the degree of wear of cutters using the method of measuring the current and vibration of the spindle.

To provide increased dynamics and rigidity of the structure, to simplify the protection of the guide axes and to increase their resource, the classical orthogonal axes were used in the general kinematic diagram of the dental complex, which are spaced as follows:

- a spindle carriage, made with two linear degrees of freedom, moving along high-precision guides of the Υ and оси axis on carriages with an interference fit, containing: a cooled high-speed spindle with pneumatic tool fixation and a productivity of 80,000 rpm, with an effective distribution of loads during linear movements in the process workpiece processing, high-performance servo controllers, 200 W AC motors, absolute current position encoders;

- the carriage of the workpiece fastening unit, containing a platform moving linearly along the high-precision guides of the X-axis on carriages with an interference fit, a compact workpiece fastening unit with two rotary axes A and B intersecting in the center of the workpiece, the design of which is completely balanced due to the absence of additional moments from its own mass, while possible angular errors have a minimal effect on the accuracy of the machine, a hermetically sealed cassette with a cartridge for tools for automatic change of cutters during operation and a tool length sensor rigidly mounted on the workpiece clamping block for unambiguous and accurate positioning by the spindle carriage mechanism during tool change , as well as a workpiece mandrel, the design of which allows, with high repeatability, to automatically fix it in the workpiece fixation mechanism. The carriage of the workpiece fastening block with a linear axis X and rotary axes A and B is necessary for the uniform distribution of loads on the linear guides, which has a positive effect on their working life, reducing the size and weight of the machine.

- the A-axis rotation mechanism, mounted on the X-axis platform, containing the A-axis shaft, a block of spring-loaded pairs of angular contact bearings with conical working bodies to eliminate backlash in the rotary axis, a 400 W high-torque servo motor with an absolute encoder;

- a mechanism for turning the B axis, installed in the body of the workpiece fastening unit, including a block of spring-loaded pairs of angular contact bearings with conical working bodies to eliminate backlash in the rotary axis, a 400 W high-torque servo motor with an absolute encoder, a workpiece fixation mechanism;

- telescopic protection system for X and Y axes, which protects the guides from processing products;

- protection system for axes Z, A and B, which insulates bearings and spindle from processing products.

To achieve the declared accuracy of the dental complex, high-precision guides of the main linear axes, carriages with low interference, as well as temperature sensors for software thermal compensation of linear expansions of parts of the dental complex are used.

When the power supply of the electronic system is turned on, thanks to the use of absolute encoders, the control system uniquely determines the location of each axis, reducing the preparation time of the dental complex for work and eliminates the stage of the control pass after each restart of the dental complex.

In order to implement a hybrid system for processing dentures, an automatic change between dry and wet milling modes was used. In the dry mode of processing the workpiece, a compressor is used to obtain compressed air, which is responsible for five functions: cooling the spindle motor, cooling the tool, removing processed products from the working area, pneumatic tool change, as well as blowing out the spindle collet before changing the tool. In a preferred embodiment, an oil-free, low-noise compressor with a moisture separator can be used. When using the wet processing mode, the cooling lubricant (coolant) is supplied by a centrifugal pump to the cooling jacket of the spindle, and from it through the nozzles into the cutting zone. The coolant performs several functions: cooling the spindle motor, cooling the tool, reducing the friction force of the tool on the part and removing the processing products of denture structures from the working area, then the coolant is filtered and cleaned is supplied to the cooling jacket of the spindle. Distilled water or distilled water with additives containing glycerin-like oils and antibacterial drugs can be used as a coolant.

Removal of contaminants from parts, forced flushing, blowing and drying of the working chamber are implemented as follows. With both methods of processing denture structures, excess air pressure is supplied to the entire space of the dental complex outside the working chamber by a centrifugal air pump to prevent treatment products from entering the area of guides, carriages, pitch-screw pairs, as well as drives of all main and auxiliary axes. Also, a centrifugal air pump is used for wet and dry processing of denture structures, for removing processing products from the working chamber of the dental complex. It creates an air flow going from the top of the working chamber to the outlet located under the processing area of dentures, sucks in particles and, thereby, cuts off the ingress of processing products from the front panel. The air passes through the filtration system and part of it, depending on the temperature, is discharged into the atmosphere, and the other part is fed back to the working area for processing dentures. In this case, the coolant flows down to the outlet, where an electrically driven damper is installed, which directs the flow of liquid or air into the appropriate intake path.

After each processing cycle, the parts of the working chamber of the dental complex are automatically washed. Detergent is supplied by means of an electric pump under pressure to movable tangential centrifugal nozzles, which, by changing the direction of spray of the detergent, treat the entire surface of the working chamber. The detergent flows into the sump of the hydraulic tank containing multi-stage filters, is cleaned and pumped back to the nozzles. Drying of the working chamber is carried out by air flow, which is created by a centrifugal air pump. As a detergent, soap essence or alcohol-based disinfectant solutions can be used, as well as other known detergents in various proportions.

The possibility of changing blanks is realized with the help of a cartridge for denture blanks, consisting of a stepper drive, a carousel-type drum for at least 2 mandrels, in which discs of material - denture blanks, with a minimum diameter of 98.5 mm are fixed, allowing to accommodate the most complete set of dental crowns for one patient. A carousel-type drum (carousel-milling) is fixed on the side of the base, made in the form of a bed, on an auxiliary rotary axis C. For automatic extraction of waste and installation of new denture blanks, during operation, all operations are carried out due to the main working axes, a fixation mechanism workpieces with a thrust thread and an electric drive, which eliminates the occurrence of emergency situations with a possible drop in pressure in the hydraulic system. With the help of an electronic computing unit, there is an automatic recognition and replacement of blanks in the process of work, which makes it possible to manufacture high-precision dentures for a long time without stopping.

To visualize the process, a working chamber has been developed, made with the ability to control the process of processing installed blanks, changing blanks and tools. An electronic computing unit (computer) with a remote touch monitor integrated into the dental complex serves to control all components, update software, control processing modes for newly created promising materials, and also to reduce the likelihood of medical errors caused by human factors.

Brief Description of Drawings

FIG. 1 "Dental complex. Design. General form"

FIG. 2 “Dental complex. Design. Front view"

FIG. 3 “Dental complex. Design. Back view"

FIG. 4 “Dental complex. B axis swing mechanism "

FIG. 5 “Dental complex. Cartridge for denture blanks "

FIG. 6 “Dental complex. Workpiece fixation mechanism "

FIG. 7 “Dental complex. Dental complex building "

The invention is illustrated by drawings.

FIG. 1 "Dental complex. Design. Front view "shows the frame 1 of the dental complex, on the side of which, on high-precision guides 12 with the help of carriages with low interference 11, the bracket 9 of the Y axis is installed, which is moved by the drive 13 of the Y axis. The position of the axis is read using an absolute encoder 14 of the Y axis. the bracket of the axis Υ on high-precision guides 10 with the help of carriages with low interference 8, the bracket 7 of the axis Ζ is installed, moving by the drive 6 of the axis Ζ. The position of the axis is read using an absolute encoder 5 of the Ζ axis. On the bracket of the axis Ζ, a spindle 4 with a cooling jacket 2 is fixed by means of a bracket 3. In the upper part of the bed 1 on carriages 21 of the X axis, a carriage of the workpiece fastening unit 17 is installed, moving linearly with the help of a drive 23 of the X axis on the guides 15 of the X axis, with on it by the block for fastening the workpiece 24 on the mechanism of rotation of the axis A. The position of the axis is read using an absolute encoder 22 of the X axis. All drive mechanisms of the X axis are protected by the protection 16 of the X axis. On the carriage of the block of fastening of the workpiece 17 there is a rotation mechanism 19 of the A axis fixed on the shaft 18 and rotating by means of the drive 20. The tool length sensor 25 is installed in the workpiece holder 24, as well as the tool cartridge 27, which is hermetically sealed by the cover 26. Also in FIG. 1 shows a working chamber 29 of a dental complex, in the lower part of which an electric shutter is installed.

FIG. 2 “Dental complex. Design. Front view "shows the dental complex from the operator's side, in the workpiece clamping block 24 of which the workpiece fixation mechanism 30 is located on the B axis, with the workpiece mandrel 31 installed in it. The rotation of the workpiece clamping unit 24 on the A axis mounted on the support 32 is read using absolute encoder 33. Also in FIG. 2, tangential centrifugal nozzles 34 are installed in the working chamber 29 for flushing the working space. On the right side of the frame 1 there is a cartridge for denture blanks 35. At the rear of the frame, a telescopic protection of the spindle carriage 36 is fixed. At the bottom of the frame, there is a hydraulic tank with a filtration system 37, an air filtration system 38 and a centrifugal air pump 39.

FIG. 3 “Dental complex. Design. Rear view "shows the dental complex from the side of the spindle, in the lower part of which there is a compressor 40, a pump 41, a centrifugal pump 42. In the left part there is a cartridge for denture blanks 35, made in the form of a rotary drum 43. Also in FIG. 3 shows the mechanism for turning the axis B.

FIG. 4 “Dental complex. Design. The mechanism for turning the B axis "shows a block for fixing the workpiece 24, in which a mechanism for turning the B axis is installed on the block of spring-loaded pairs of angular contact bearings with conical working bodies 45, rotating by the B axis drive 46. The position of the B axis is read using an absolute encoder 47. In the block of spring-loaded pairs of angular contact bearings, there is a workpiece fixing mechanism 30, which consists of a B axis shaft 48, a fixing screw with a thrust thread 49 and an electric drive 50.

FIG. 5 “Dental complex. Design. Cartridge for denture blanks "depicts a carousel-type drum with installed mandrels 31, fixed on an auxiliary axis C, rotating with a stepper drive 51.

FIG. 6 “Dental complex. Design. The workpiece fixing mechanism "is shown in section the B-axis shaft with the fixing screw 49, driven by the electric drive 50, with the workpiece mandrel 31 installed.

FIG. 7 “Dental complex. Design. The body of the dental complex "shows schematically the body of the dental complex 52 with a movable remote touch monitor 53, in the lower part of which the filtration system with a hydraulic tank 37 is schematically shown.

Implementation of the invention

The advantages of the layout of the dental complex:

- applied classical orthogonal axes in the general kinematic diagram of the dental complex, which simplify the design, manufacture of the structure and calibration. All axles are made in the form of metal cylindrical rods;

- a modular design has been applied, which allows varying the layout of the dental complex and quick replacement of failed components, which ensures high maintainability;

- a simple, compact and functional cartridge for denture blanks for at least 2 discs is used, protected from the ingress of processing products, with convenient access to extracting waste processing products through the front panel and installing new ones in the process, which allows non-stop manufacturing of high-precision dentures, while the cartridge is performed as a separate module, which makes it possible to install and replace it;

- designed a cassette containing a cartridge for instruments with a capacity of 2 to 20 cutters, located in the block for holding blanks, easily replaceable and uniquely positioned through the front panel of the dental complex. The instrument cartridge is closed with a motorized cover when not in use. When changing tools, the cover opens, making it easy to change the tool.

Example: If it is necessary to manufacture dentures in small quantities, then 2-8 cutters are placed in the cartridge. If it is necessary to manufacture dentures in large quantities, then 10-20 cutters are placed in the cartridge. The number of cutters used, in the specified interval, allows the processing of denture structures in small and large medical institutions in terms of the number of services provided.

- a tool length sensor is used, rigidly mounted on a compact block for fixing the workpiece, separately from the cassette with the tool cartridge, with unambiguous and accurate positioning;

- all operations for changing the tool and workpieces are carried out at the expense of the main working axes;

- the spindle carriage mechanism has only two degrees of freedom, axis Υ and Ζ, which provides increased rigidity and accuracy of the structure, the efficiency of load distribution during linear movements, which simplifies the protection of the guide axes, and also allows them to increase their resource;

- the design of the X axis provides the possibility of using simple protection of the axle guides from processing products, as well as effective distribution of loads on the carriages of linear guides, which has a positive effect on their resource;

- the design of the rotary axes A and B is completely balanced due to the absence of additional moments from its own mass, and the axes of rotation intersect in the center of the workpiece, which ensures maximum accuracy, while angular errors have a minimal effect on the workpiece processing;

- the possibility of dry and wet processing of workpieces, as well as guaranteed accuracy - 5 microns, allows processing not only materials traditionally used in dentistry, but also modern titanium premills and lithium disilicate without trying on;

- the deviation of the rotary axis A by an angle of ± 30 ° and the axis B by 360 ° during processing is provided, as well as the ability to rotate the A axis by 120 ° for convenient replacement of the cartridge for tools and maintenance of the workpiece holder with the door of the working chamber open;

- when the machine is turned off, the spindle can be freely lowered to the lower position, which ensures the safety of operation of the dental complex and simplifies the development of software control;

- a simple and reliable telescopic structure of protection of the guiding axes of the Cartesian coordinate system of the dental complex is used;

- a monolithic rigid bed with a high degree of vibration absorption and noise insulation has been developed, which allows to increase the rigidity of the dental complex, uniform distribution of loads, and reduce the dimensions and weight of the machine. All structural elements of the complex are fixed on the bed.

- a simple, reliable and technological design of the workpiece mandrel is used, as well as a mechanism for fixing it in the B axis, resistant to contamination;

- to eliminate the backlash of the pivot axes, spring-loaded pairs of angular contact bearings with tapered working bodies are used;

- high-precision guides of the main linear axes and carriages of guides with low interference are used;

- introduced absolute encoders of the position of all axes, instead of incremental ones, to unambiguously determine the location of each axis, as well as to reduce the preparation time of the dental complex for work and to exclude the inspection pass stage after each restart of the machine. Absolute encoders can be magnetic or optical;

- integrated temperature sensors for software compensation of thermal expansion of parts of the dental complex, preventing inaccuracies in processing and allowing cutting the workpiece in a wide temperature range;

- applied controllers for software self-diagnostics of axle drives by current consumption, as well as controllers for absolute software support of the degree of wear of cutters by the method of measuring the current and vibration of the spindle;

- cleaning of the working chamber is realized by automatic spraying and collection of detergent under pressure;

- provided convenient access to the working chamber with the ability to visually control the processing of installed workpieces, change workpieces and tools;

- the electronic computing unit integrated into the dental complex, equipped with a remote touchscreen monitor, provides not only the ability to control all components of the dental complex, but also allows, if necessary, to update the software of the strategy and processing modes for the created new promising materials, and also reduces the likelihood of doctors human error;

- a rigid fastening of the workpiece with a mandrel in the B axis is made due to the use of a thrust thread and an electric drive, which excludes the occurrence of emergency situations when the pressure in the hydraulic system drops;

- a consistent and logical system for coding workpieces and tools with display on the control panel;

- small dimensions and low noise level during operation allow the use of this dental complex in the conditions of dental offices, clinics, denture departments.

Claims (1)

Dental complex for creating denture structures, characterized in that it contains a frame, a working chamber, a block for fastening denture blanks, a kinematic block, a cartridge for instruments, characterized in that it contains a cartridge for denture blanks; air pump, compressor, pump for coolant supply, electric pump, hydraulic tank, control system, electronic computing unit; the hydraulic tank is provided with a pallet; the air pump is configured to remove impurities from the parts of the complex and dry the working chamber; the compressor is configured to cool the instrument, pneumatically change the instrument and remove the products of processing denture structures; the electric pump is configured to supply a detergent; the block for fastening denture blanks is equipped with a cartridge for instruments; the control system is configured to determine the location of each axis and is equipped with absolute encoders; the kinematic unit is equipped with a mechanism for controlling the rotation of the axes; cartridge for denture blanks is made in the form of a carousel drum; the tool cartridge is designed to accommodate from 2 to 20 cutters.

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