CN110321370B

CN110321370B - Tool holder matching method based on RBR and tool holder matching method of gear hobbing machine

Info

Publication number: CN110321370B
Application number: CN201910550861.XA
Authority: CN
Inventors: 苏丹; 鄢萍
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2019-06-24
Filing date: 2019-06-24
Publication date: 2021-07-27
Anticipated expiration: 2039-06-24
Also published as: CN110321370A

Abstract

The invention discloses a tool and fixture matching method based on RBR and a tool and fixture matching method of a gear hobbing machine, and a matching rule base is established; extracting relevant processing task information as a fact condition a for tool matching; a conclusion deduced by the tool matching rule of which the condition part is matched with the factual condition a is taken as a temporary tool set; the intersection of the temporary cutter set and the cutter resource set is a cutter set H; extracting the clamping information of the cutter set H and the processing machine tool as a fact condition b of cutter bar matching, and using a conclusion deduced by a cutter bar matching rule of which the condition part is matched with the fact condition b as a temporary cutter bar set; the intersection of the temporary cutter bar set and the cutter bar resource set is a cutter bar set B, and a cutter set H is updated according to the cutter bar set B; extracting workpiece clamping information as a factual condition c for fixture matching, and using a conclusion deduced by a fixture matching rule of which the condition part is matched with the factual condition c as a temporary fixture set; the intersection of the temporary clamp set and the clamp resource set is a clamp set F; the tool holder set T ═ hb F }.

Description

Tool holder matching method based on RBR and tool holder matching method of gear hobbing machine

Technical Field

The invention belongs to the technical field of machining and manufacturing, and particularly relates to a tool holder matching method.

Background

The gear as a component element of the gear system has the characteristic of wide application and plays a key role in mechanical equipment such as wind power generation, aerospace, automobiles, shield machines and the like; the quality of the dynamic characteristics of the device directly influences the working performance of the whole device. For machining gears, hobbing is the most widely used gear cutting method at home and abroad at present, and the quantity of hobbing machines in some countries accounts for about 45 to 50 percent of the total quantity of all gear machine tools. Therefore, a hobbing machine, which is a typical one of manufacturing machines, has a significant influence on the manufacturing and machining of gears, and especially, the reasonable selection of a hobbing machine tool fixture has an important significance in the machining process of gears. However, the selection and matching of the domestic hobbing machine tool clamp still depends on the matching of a process worker according to own experience, and the problems of large workload, low efficiency and difficult prediction and control of processing quality exist; therefore, the decision making process in the manufacturing process is strengthened by utilizing the data in the manufacturing process and the force for calculating intelligence, the intelligent matching of the hobbing machine tool clamp is realized, the tool resources in the manufacturing process are helped to be selected and matched, and the method has important significance for reasonably utilizing the tool clamp and improving the processing efficiency and quality.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a tool holder matching method based on RBR, which solves the technical problem that the tool, the tool bar and the tool holder cannot be simultaneously combined and matched in the prior art in combination with the actual situation of workshop tool holder resources.

In order to solve the technical problems, the technical scheme of the invention is as follows: a tool holder matching method based on RBR comprises the following steps:

step 1: respectively determining matching requirements of a cutter, a cutter bar and a clamp according to a machining principle and an actual machining condition, and establishing a matching rule base according to the matching requirements; the matching rule base comprises a cutter matching rule, a cutter bar matching rule and a clamp matching rule; each matching rule is expressed in a production rule form and comprises a rule serial number, a condition part and a conclusion part;

step 2: acquiring processing task information and an actual tool holder resource set; the processing task information comprises workpiece parameter information, processing technology information and clamping information; the processing technology information comprises the precision grade of the workpiece, the surface roughness of the workpiece, procedures and processing machine tool information, and the processing machine tool information comprises clamping information of the processing machine tool; the clamping information comprises workpiece clamping information including a workpiece clamping type and a workpiece clamping size; the actual tool and fixture resource information comprises a tool resource set, a tool bar resource set and a fixture resource set;

and step 3: extracting workpiece parameter information and processing process information as a fact condition a of the tool matching problem and sending the fact condition a into a database;

and 4, step 4: extracting a condition part in the tool matching rule, comparing the condition part with a factual condition a in a database, and using a conclusion deduced by the tool matching rule with the condition part matched with the factual condition a as a temporary tool set;

and 5: comparing the temporary tool set with the tool resource set in the actual tool clamp resource information, and judging whether the intersection of the temporary tool set and the tool resource set is an empty set; if yes, sending a purchase request and finishing the matching process; if not, taking the intersection of the temporary tool set and the tool resource set as a tool set H, acquiring tool parameter information including the shape parameters according to the tool set H, and entering the step 6:

step 6: extracting the shape parameter information of each cutter in the cutter set H and the clamping information of the processing machine tool in the processing task information as a factual condition b of the cutter bar matching problem and sending the factual condition b into a database;

and 7: extracting a condition part in the cutter bar matching rule, comparing the condition part with a factual condition b in a database, and using a conclusion deduced by the cutter bar matching rule of which the condition part is matched with the factual condition b as a temporary cutter bar set;

and 8: comparing the temporary cutter bar set with the cutter bar resource set in the actual cutter holder resource information, and judging whether the intersection of the temporary cutter bar set and the cutter bar resource set is an empty set; if yes, sending a purchase request and finishing the matching process; if not, taking the intersection of the temporary cutter bar set and the cutter bar resource set as a cutter bar set B, and entering the step 9;

and step 9: acquiring a complement of a candidate cutter bar set in the temporary cutter bar set, and updating a cutter set H according to the complement: removing the cutter set corresponding to the complement set from the cutter set H;

step 10: extracting workpiece clamping information in the processing task information as a factual condition c of the fixture matching problem and sending the factual condition c into a database;

step 11: extracting a condition part in the fixture matching rule, comparing the condition part with a factual condition c in a database, and using a conclusion deduced by the fixture matching rule with the condition part matched with the factual condition c as a temporary fixture set;

step 12: comparing the temporary clamp set with the clamp resource set in the actual tool clamp resource information, and judging whether the intersection of the temporary clamp set and the clamp resource set is an empty set; if yes, sending a purchase request and finishing the matching process; if not, taking the intersection of the temporary clamp set and the clamp resource set as a clamp set F, and entering the step 13;

step 13: calculating a tool and fixture set T, wherein T is { H B F }, according to the updated tool set H, the tool bar set B and the fixture set F; and taking the tool holder set T as a tool holder matching scheme meeting the requirement of a processing task, wherein the elements in the set H and the set B have a mapping relation.

Further, tool matching rules meeting the fact condition a, tool bar matching rules meeting the fact condition b and fixture matching rules meeting the fact condition c are stored in a temporary rule set in a database; when step 4, step 7 or step 11 is carried out, firstly, whether the temporary rule set has matching rules meeting corresponding factual conditions is judged, if yes, the condition part of the matching rules is extracted from the temporary rule set and compared with factual conditions in the database; if not, the conditional part of the matching rule is extracted from the matching rule base and compared with the factual condition in the database.

Further, the tool matching requirement, the cutter bar matching requirement and the clamp matching requirement are respectively as follows:

the selection and matching requirements of the cutter are as follows: simultaneously meets the requirement R of the finished piece_HmThe process requirement R_HcAnd the clamping requirement R_Hf(ii) a Part requirement R_HmThe matching requirement of the processing cutter information is shown when the processed gear finished product reaches the corresponding standard from the perspective of the gear finished product; process requirement R_HcThe matching requirement of the information of the machining tool is shown when the machined gear finished product reaches the corresponding standard from the viewpoint of the machining process; clamping requirement R_HfThe clamping requirement required to be met by the cutter in the machining process is shown, wherein the clamping requirement comprises the clamping between the cutter and the cutter bar;

the matching requirement of the cutter bar is as follows: meet the cutter bar clamping requirement R_BfClamping requirement R_BfThe clamping requirements required to be met by the cutter bar in the machining process are shown, wherein the clamping requirements comprise clamping between the cutter bar and a cutter and clamping between the cutter bar and a machine toolClamping;

the selection and matching requirements of the clamp are as follows: meet the clamping requirement R of the clamp_FfClamping requirement R_FfThe clamping requirements required to be met by the clamp in machining are shown, wherein the clamping requirements comprise clamping between the clamp and a workpiece.

The invention also provides a tool holder matching method of the gear hobbing machine, which adopts the tool holder matching method based on the RBR; the cutter is a hob, and the information of the hob comprises tooth profile parameter information, blade profile parameter information, appearance parameter information, structural parameter information, processing technology information and coating material information; the processing workpiece is a gear or a gear shaft; the workpiece parameter information comprises a normal modulus, a normal pressure angle, a spiral angle, a tooth crest height coefficient, a tip clearance coefficient and a rotation direction.

Compared with the prior art, the invention has the following beneficial effects:

1. according to the invention, a tool holder set which can meet the basic requirements of the processing task is screened out according to the workpiece requirements, the process requirements and the clamping requirements of the processing task, so that a reliable optimal range is provided for the subsequent tool holder selection; the tool holder set is a combined matching of a tool, a tool bar and a clamp, the tool holder set is different from the prior art which only carries out the matching of the tool, the matching process is combined with the actual situation of workshop tool holder resources, the selected tool bar and the selected clamp can be actually provided, and the practicability is high.

2. The matching method has certain self-organization, can meet the requirement of rapidly and scientifically matching the tool holders for the processing tasks under the condition of no external manual intervention in the process of matching the tool holders for the processing tasks, and can be integrated into a system, so that the traditional manual matching mode of the hobbing machine tool holders is broken, and the intellectualization of the matching of the hobbing machine tool holders is realized.

3. The invention constructs a hobbing machine tool fixture matching model based on rule reasoning (RBR) to realize preliminary matching of the tool fixture, connects the problems and answers in the related fields in series in a rule form in the process, and formally expresses the experience knowledge, and has the advantages of simple knowledge form expression, strong reasoning capability and easy realization.

Drawings

FIG. 1 is a flow chart of a RBR based tool holder mating method;

FIG. 2 is a representation of a set of tool holders T in a three-dimensional coordinate space.

Detailed Description

Referring to fig. 1, a tool holder assembling method based on RBR is characterized by comprising the following steps:

step 13: calculating a tool and fixture set T, wherein T is { H B F }, according to the updated tool set H, the tool bar set B and the fixture set F; and taking the tool holder set T as a tool holder matching scheme meeting the requirements of the processing task, wherein the elements in the tool set H and the tool bar set B have a mapping relation.

If the set T is not empty, the set T is as shown in FIG. 2; in the figure, the x axis has 3 coordinates H, B and F, namely a hob set H, a cutter bar set B and a clamp set F; h with x coordinates identical to H, B and F₁ H₂ … H_n}、{B₁ B₂ … B_mAnd { F }₁ F₂… F_kRespectively representing the type of the hob, the type of the cutter bar and the type of the clamp which are screened according to the processing task; wherein the z-axis represents the number of alternative tool holders corresponding to each tool holder type on the xy-plane; all tool holders represented in fig. 2 together constitute a tool holder set T.

In order to improve the matching efficiency, a cutter matching result obtained by inference according to the fact condition a, a cutter bar matching result obtained by inference according to the fact condition b and a clamp matching result obtained by inference according to the fact condition c are stored in a database; before the step 4, the step 7 or the step 11, firstly judging whether a database contains a solution of the problem, if so, directly obtaining a matching conclusion; if not, the conditional part of the matching rule is extracted from the matching rule base and compared with the factual condition in the database.

The specific matching requirements of the hob, the cutter bar and the clamp are as follows:

the parameters of the hob mainly influence the parts and the process in the processing, and the matching requirement of the hob is mainly determined according to the hobbing principle; for clamping, the method mainly comprises the steps of clamping between a cutter bar and a machine tool, clamping between a hob and the cutter bar and clamping between a clamp and a workpiece; the specific matching requirements of the hob, the cutter bar and the clamp are as follows:

selection and matching requirements of hobbing cutters

Tooth profile parameter information: the gear hob is a cutter for processing a gear according to a generating method, the hob can be regarded as a gear meshed with a processed gear in the processing process, so the tooth profile parameters of the hob depend on the parameter information of the processed gear, and the specific rule is shown in table 1:

TABLE 1 tooth profile parameter information matching rules

Blade shape parameter information: the front angle is 7-9 degrees, and the front angle is 7-9 degrees or 12-15 degrees during rough machining; the top relief angle is 10-12 degrees, and the side relief angle is 2-3 degrees.

And (3) appearance parameter information: the rotary direction of the hob is generally consistent with that of a gear to be processed; the number of heads affects the precision of finished products and the machining efficiency in the machining of gear hobbing, and for the hob used for finish machining, the number of heads is generally selected from the viewpoint of the machining precision and the machining smoothness, so that a single-head hob is selected during finish machining; since both precision and efficiency are required for rough machining and semi-finish machining, there is no clear requirement for the number of heads, and therefore, it is not a hard standard in matching.

Structural parameter information: the hole type hob belongs to a universal type and needs to be matched with a cutter bar for use; the rod-type hob can be directly assembled on a machine tool for use and belongs to a special type; therefore, the selection is only for the hole hob of the general type.

Processing process information: the pre-grinding hob belongs to a rough machining hob, and the pre-shaving hob belongs to a semi-finishing hob which are respectively used before grinding and shaving processes; the selection of the hob accuracy grade depends mainly on the accuracy of the gear to be machined. The relationship between the accuracy of the hob and the accuracy of the gear to be machined during the finish machining is shown in table 2:

TABLE 2 finishing hob accuracy matching rules

Gear precision	Stage 7	Stage 8	Grade 9	Lower than 9 grade
					Hob accuracy	AA	A	B	C

For rough machining or semi-finish machining, a hob before shaving is selected with A-level precision; selecting B-level precision for a hob before grinding; other C-level precisions may be selected.

Coating material information: the common high-speed steel is used for the first hobbing speed V of less than or equal to 40-50 m/min, and the common steel number is W18Cr 4V; the high-performance high-speed steel is used for the second hobbing speed V of 60-90 m/min, such as aluminum high-speed steel (501) and vanadium high-speed steel (V)₃N), cobalt high speed steel (M)₄₂) Etc.; the materials suitable for the third hobbing speed V which is more than or equal to 150m/min are powder metallurgy high-speed steel and hard alloy.

The matching requirement of the cutter bar:

the cutter bar is mainly used for connecting a machine tool and the hob in gear machining of the gear hobbing machine so as to fix the hob; the clamping requirement comprises a cutter bar and a hob, and the clamping between the cutter bar and a machine tool belongs to the shaft hole matching; according to the principle of shaft hole matching and the actual machining condition of hobbing, the matching of the cutter bar follows the following principle:

1) the nominal diameter of the cutter bar is the same as the nominal aperture of the machine tool clamping cutter bar; due to the presence of the positioning device on the machine tool, an

In order to meet the requirement of detachable cutter bar, clearance fit is adopted between the cutter bar and the machine tool.

2) The cutter mounting diameter of the cutter bar is the same as the nominal aperture of the hob; because the cutter bar can axially position the hob, and

in order to meet the detachable requirement of the hob, clearance fit is adopted between the cutter bar and the hob.

3) The maximum cutter mounting length of the cutter bar is larger than the total length of the hob.

4) The key width of the cutter bar is matched with the key slot width of the hob.

Thirdly, the selection and matching requirements of the clamp

The fixture has the main function of fixing a machined workpiece in gear machining of the gear hobbing machine, and ensures that the position of the machined workpiece cannot deviate in the machining process, so that the machining precision is ensured. The clamping modes of the used clamp are different according to different shapes of the processed workpiece; in the machining of gear hobbing, the clamping mode of a clamp is mainly divided into two major types, one type is used for machining workpieces such as gear shafts, belongs to the clamping mode of a chuck and needs to be matched with an ejector pin for use; the other type is used for processing workpieces such as gears, and belongs to a thread pressing mode; after the clamping mode of the clamp is determined, different clamp types need to be further selected according to the size of the workpiece, so the selection rule of the clamp is as follows:

1) the clamping mode is selected as a clamp for clamping a chuck for processing workpieces such as gear shafts.

2) A clamp with a thread pressing mode is required to be selected for machining workpieces in flat shapes such as gears.

3) The clamping size of various processing workpieces is required to meet the size range of effective clamping of various clamps.

Establishment of matching rule base

The rules in the gear hobbing machine tool fixture matching model are expressed in the form of 'IF A THEN B' by adopting a production rule expression method; the rule base is divided into three major parts, wherein the first part is a rule serial number, the second part is a condition part, and the third part is a conclusion part; when a fact is matched with a condition part in a rule, the rule is used, and the conclusion reasoned by the rule can be used as a condition of the next inference. Taking the cutter bar and the clamp as an example, the rule of part generation is as follows:

r1: IF (machine tool clamping aperture is 26mm) AND (hob aperture is 32mm) AND (hob full length is 85mm) AND (key width is 8.1mm) THEN (hob type number is 1101001)

R2: IF (machine tool clamping aperture is 26mm) AND (hob aperture is 27mm) AND (hob full length is 70mm) AND (key width is 6.08mm) THEN (type number of hob bar is 1101006)

R3: IF (machine tool clamping aperture is 26mm) AND (hob aperture is 27mm) AND (hob full length is 65mm) AND (key width is 6.08mm) THEN (cutter bar type number is 1101008)

R4: IF (workpiece type & gear shaft type) AND (workpiece clamping size & lt 15mm) THEN (clamp type & number & gt 1272003)

In the embodiment, a gear machining workshop of a certain machine tool factory in Chongqing is taken as an example for case research, data in the following tables are all from the gear machining workshop, and the existing cases are as follows:

now, finish machining is needed for the bevel gear shaft with a normal modulus of 3, and part of information is shown in table 3:

TABLE 3 information of workpiece parameters of gear part to be machined

Firstly, determining a hob set

According to the hob matching rules herein, the parameters of the hobs required for the gears, for which the machining parameter information and process requirements are as shown in table 3, are shown in table 4; the base materials of the common hole type hob in the workshop are all W18Cr4V, and the coating materials are all TiN, so that the coating material information of the hob is not included in the table 4; according to the requirements in table 4, the hobs in the warehouse of the gear processing workshop are screened and matched to obtain a hob set H meeting the processing conditions, and part of relevant information of the hob set H is shown in table 5.

TABLE 4 Hob parameter requirements

TABLE 5 hob partial parameter information

Hob type name	Type numbering	Outer diameter (mm)	Aperture (mm)	Full length (mm)
					Fine hob M3	1151002	80	32	80
Fine hob M3	1151005	80	32	71
					Fine hob M3	1151006	70	27	60

Determining cutter bar set

For the gear machining workshop, the clamping matching between the universal hobbing cutter bar and the hobbing machine tool is standardized, so that the cutter bar only needs to consider the clamping constraint with the hobbing cutter; then, the cutter bars in the workshop storehouse are screened and matched to obtain a cutter bar set B matched with the hob set H, and part of relevant information is shown in table 6:

TABLE 6 tool shank portion parameter information

Name of type of tool holder	Type numbering	Diameter of cutter	Maximum length of knife
				Universal cutter bar for hobbing	1101001	32	85
Universal cutter bar for hobbing	1101006	27	70
				Universal cutter bar for hobbing	1101008	27	65

Thirdly, the hob set is updated

According to the information in table 6, the hob types in table 5 all have a matched hob bar type, so the hob types in the set H do not need to be removed.

Determining clamp set

The workpiece is clamped by a chuck in a clamping way because the workpiece to be processed is a gear shaft; the fixture in the workshop storehouse is screened and matched to obtain a fixture set F matched with the processing task, and part of relevant information is shown in a table 7:

TABLE 7 Fixture part parameter information

Name of clamp type	Type numbering	Clamping mode	Clamping range (mm)
				Universal fixture for hobbing	1272003	Clamping head clamping	0～15

Determining a tool holder type set

The tool holder set T may be determined to be the tool holder types in tables 5-7; the hob, arbor and fixture information in the final candidate set of toolholders T are shown in tables 8 to 10, respectively.

TABLE 8 Hob parameter information

TABLE 9 tool shank parameter information

TABLE 10 Clamp parameter information

Claims

1. A tool holder matching method based on RBR is characterized by comprising the following steps:

the tool matching requirement, the cutter bar matching requirement and the clamp matching requirement are respectively as follows:

the matching requirement of the cutter bar is as follows: meet the cutter bar clamping requirement R_BfClamping requirement R_BfIndicating knifeThe clamping requirements required to be met in the machining process of the rod comprise clamping between a cutter bar and a cutter and clamping between the cutter bar and a machine tool;

the selection and matching requirements of the clamp are as follows: meet the clamping requirement R of the clamp_FfClamping requirement R_FfThe clamping requirement required to be met by the clamp in the machining process is shown, wherein the clamping requirement comprises the clamping between the clamp and a workpiece;

2. An RBR-based tool holder matching method according to claim 1, characterized in that the tool holder matching result inferred from the factual condition a, the tool bar matching result inferred from the factual condition b and the holder matching result inferred from the factual condition c are stored in the database; before the step 4, the step 7 or the step 11, firstly judging whether a database contains a solution of the problem, if so, directly obtaining a matching conclusion; if not, the conditional part of the matching rule is extracted from the matching rule base and compared with the factual condition in the database.

3. A method of selecting a tool holder for a gear hobbing machine, characterized by using the RBR-based tool holder selecting method according to claim 1; the cutter is a hob, and the information of the hob comprises tooth profile parameter information, blade profile parameter information, appearance parameter information, structural parameter information, processing technology information and coating material information; the processing workpiece is a gear or a gear shaft; the workpiece parameter information comprises a normal modulus, a normal pressure angle, a spiral angle, a tooth crest height coefficient, a tip clearance coefficient and a rotation direction.

4. The method of claim 3 wherein hob assembly is as follows:

tooth profile parameter information: the gear hob is a cutter for processing a gear according to a generating method, and the hob can be regarded as the gear meshed with the processed gear in the processing process, so the tooth profile parameters of the hob depend on the parameter information of the processed gear;

blade shape parameter information: the front angle is 7-9 degrees, and the front angle is 7-9 degrees or 12-15 degrees during rough machining; the top relief angle is 10-12 degrees, and the side relief angle is 2-3 degrees;

and (3) appearance parameter information: the rotating direction of the hob is consistent with that of the processed gear; the number of heads affects the precision of finished products and the machining efficiency in the machining of gear hobbing, and for the hob used for finish machining, the number of heads is selected from the aspects of machining precision and machining smoothness, so that a single-head hob is selected during finish machining; for rough machining and semi-finish machining, precision and efficiency need to be considered, so that no clear requirement is made on the number of heads;

structural parameter information: the hole type hob belongs to a universal type and needs to be matched with a cutter bar for use; the rod-type hob can be directly assembled on a machine tool for use and belongs to a special type; therefore, the selection is only performed on the general hole type hob;

processing process information: the pre-grinding hob belongs to a rough machining hob, and the pre-shaving hob belongs to a semi-finishing hob which are respectively used before grinding and shaving processes; the selection of the hob precision grade mainly depends on the precision of the processed gear;

coating material information: the common high-speed steel is used for the first hobbing speed V is less than or equal to 40-50 m/min; the high-performance high-speed steel is used for a second hobbing speed V of 60-90 m/min; the powder metallurgy high-speed steel and the hard alloy are suitable for the third hobbing speed V which is more than or equal to 150 m/min.

5. The method of claim 3 wherein the cutter bar is used in gear hobbing machine gear machining to connect the machine tool to the hob to secure the hob; the clamping requirement comprises a cutter bar and a hob, and the clamping between the cutter bar and a machine tool belongs to the shaft hole matching; according to the principle of shaft hole cooperation, the cutter bar matching requirement is as follows by combining the actual processing condition of hobbing: the nominal diameter of the cutter bar is the same as the nominal aperture of the clamping cutter bar of the hobbing machine, and the cutter bar is in clearance fit with the machine tool in order to meet the requirement of detachable cutter bar due to the positioning device on the machine tool; the cutter mounting diameter of the cutter bar is the same as the nominal aperture of the hob, the hob can be axially positioned by the cutter bar, and the cutter bar and the hob are in clearance fit to meet the detachable requirement of the hob; the maximum cutter mounting length of the cutter bar is larger than the total length of the hob; the key width of the cutter bar is matched with the key slot width of the hob.

6. The method for selecting a tool holder for a hobbing machine according to claim 5, wherein the tool holder is used for fixing a workpiece to be machined in gear machining of the hobbing machine, and the position of the workpiece to be machined is ensured not to be shifted in the machining process, so that the machining precision is ensured; in the machining of gear hobbing, according to the different appearance shapes of the machined workpiece, the workpiece clamping types are divided into two main types: one is used for processing workpieces of gear shafts, belongs to a chuck clamping mode and needs to be matched with an ejector pin for use; the other type is used for processing workpieces such as gears, and belongs to a thread pressing mode; after the clamping mode of the clamp is determined, different clamp types need to be further selected according to the size of the workpiece, and therefore, the clamp selection requirements are as follows: selecting a chuck type clamp for a machining workpiece of the gear shaft; selecting a thread pressing type clamp for a gear-like flat-shaped processing workpiece; the workpiece clamping size of various processing workpieces needs to meet the size range of effective clamping of various clamps.