1、MIL-T-qb398 12 = 7777906 0311731 T y r #-ci-aq MIL-T- “G” for production gages, “M” for Molds, “P” for patterns, “T” special assembly equip- ment and all other tools. 2. Sequence of opelation num- ber; 1, 2, 3 etc. 3. Assigned Government LNo. 4. Gyade of Tool; Letter A or 3 Exampie : T1-09733124A (c
2、) Name, type, model number and capacity of machine, when tool is used on a power machine. Ex- ample : Lathe, turret, electrocycie No. 1, Warner and in addition Grade A and B tools shall meet the tolerances specified on the tool draw- ings and shall maintain accuracy while in use. 3.1.7 Workmanship.
3、Workmanship shall be in accordance with best toolmaking practice consistent with the grade of tools specified in the contract. 3.1.8 Identifiation. Grade A and B tools shall be engraved, stamped or etched with the following identification : (a) Army and munitions command Symbol (USA-MU) . . (b) Tool
4、 nomenclature. (c) Tool number. (d) Component nomenclature. . (e) Instrument nomenclature. 3.1.8.1 Tool number. The tool number shall consist of four parts ; Contractor identifica- tion symbol; Tool category and sequence of operation symbol ; Componen item drawing number; and the component drawing r
5、e- vision symbol, if any. The tool number shall be assigned by the contractor. Example : GTSA7432561-B 3.2 Detail requirements. 3.2.1 Type I-cutting tools. 3.2.1.1 Material. - 3.2.1.1.1 Grude A. The material used in this grade of cutting tool shall be composed of carbide patches, and inserts, or ele
6、ctrolized high speed tool steel. 3.2.1.1.2 Grade B. The material used in this grade of cutting tool shall be composed of high speed tool steel. In cases where harden- ing would cause burn away or distortion of thin sections, high carbon tool steel shall be used. MIGT-46398 (MU) 3.2.1.2 Design. Grade
7、 A and B. Unless otherwise specified these cutting took shall be backed off without changing the shape or size of the form. Where backing off cannot be held true to form a template or profile gage shall be supplied with the form tool in order to facilitate regrinding or sharpening. 3.2.1.3 Heat trea
8、tment and fim? finish. Grade A gh the bottom of the press, the straight side wall portion of the die shall be kept to a iriaxiiIin1 length. This length shall be deter- mined by the material under process, the thickness of the blank and the class of tool. This requirement applies to piercing or shav-
9、 ing dies and those requiring bottom clear- ance. Where the blank is ejected through the top of the die by a mechanical ejector, the straight side wall length shall be equaI to the thickness of the die unless otherwise specified. 3.2.2.2.4 Clearance. To insure clean blanks, the clearance between the
10、 punch and the die shall be kept to a minimum. The required clearance is determined by the material and its thickness. 3.2.2.2.5 Relief. The relief clearance of the die shall be large enough to permit free passage of the blank or slug, but not enough to permit the blank to tumble and hang up. 3.2.2.
11、2.6 Stripper. When a stripper is re- quired it shall be made of hardened tool steel or pack hardened machine steel actuated by springs or rubber. When short action is required, the stripper shall be made of cork or similar composition. The stripper shall complete its function with every cycle of ope
12、ration. Manually operated strippers shall not be permitted. 3.2.2.2.7 Ejector. The ejector shall be a knockout or air blast type. An ejector com- posed of cork or composition is acceptable, provided it completes its function with every cycle of operation. Manually operated ejec- tors shall not be pe
13、rmitted. 3.2.2.2.8 Alignment. The alignment of the punch and die shall be maintained to-prevent hang up, shearing, pushover or undue strain while under working pressure. 3.2.2.3 Heat treatment. All wearing sur- faces of Grade A and B punches and dies shall be heat treated to obtain maximum hardness
14、and still retain sufficient tough- ness .to resist chipping, cracking, or crum- bling under working pressure. Thin cutting * sections shall be treated to obtain max mum toughness and sufficient hardness to prevent galling and spalling. When. heat treating methods do not produce the c.:-:-: ,zits ins
15、erts may be used. 3.2.2.4 Finish. To insure accuracy) and to eliminate soft skin due to decarburization in hardening, all working or wearing surfaces shall be finish ground or polished. Where grinding is not practical, the tool steel used shall be of a type which shall not change during the hardenin
16、g process beyond the allowable limits. Decarburization shall be avoided and all working or wearing surfaces shall be stoned 01 polished. 3.2.2.5 Performance. Grade A punches and dies shall perform multiple operations in one cycle or in stages, as in the case of progres- sive dies. Grade B punch and
17、dies shaiI perform one or more operations in one cycle and may consist of a family of punches and dies to complete the required operations. 3.2.2.6 Die sets. The use of commercial die sets shall be permitted provided the proper grade and material are selected. Used die sets are not permitted. 3.2.2.
18、7 Guide pins and bushings. The use of commercially hardened and ground steel guide pins and bushings is permitted. 3.2.3 Type III forging dies Grade A and B. 3.2.3.1 iMntel.inl. The steel selected for these forging dies shall be of a tjpe which after heat treatment shall possess sufficient red hardn
19、ess and maximum toughness qualities. 3.2.3.2 Design. Grade A dies shall be of multiple cavity design; Grade B dies shall be of single cavity design. 3.2.3.2.1 Inserts. Inserts may be used pro- vided they are locked in place to prevent any movement. They can also be used to over- come complicated hea
20、t treating conditions. They should not be used where their applica- tion would be detrimental to the die. . 3.2.3.2.2 Sections. To facilitate mainte- nance, acciiracy, and machinability, sections may be used provided they are properly in- 4 Provided by IHSNot for ResaleNo reproduction or networking
21、permitted without license from IHS-,-,-NIL-T-Yb378 12 777770b 0333735 7 stalled and are not weakened by excessive use of screws and dowel pins. Sections lack- ing adequate support, backing or conditions that would weaken the die should be avoided. 3.2.4 Type IV die casting dies-Grade A and B. 3.2.4.
22、1 Materiat. The steel selected for these dies should be of a type which after heat treatment has sufficient hardness and strength to resist heat cliecking. 3.2.4.2 Design. Grade A dies shall be of multiple cavity design. Class E dies shall be of single cavity design. 3.2.4.2.1 Inserts. To facilitate
23、 maintenance, inserts may be used provided they have sufficient reinforcement and are locked in place to prevent any movement detrimental to the die. Inserts may also be used to over- come complicated heat treating conditions. They should not be used where their applica- tionwould be detrimental to
24、the die. 3.2.4.2.2 Sections. To facilitate mainte- nance, accuracy, and machinability, sections may be used provided they are properly in- stalled, and are not weakened by excessive use of screws and dowel pins. Sections lack- ing adequate support, backing, or conditions that would weaken the die sh
25、ould be avoided. 3.2.4.2.3 Vents. Vent size shall be sufficient to allow proper venting but shall not be excessive to the extent that heavy flashes would result in excessive deburring opera- tions. 3.2.4.2.4 Ejector. The ejector shall be the mechanical type. The activation of the ejector shall be op
26、tional, either air, hydraulic, or mechanical. 3.2.4.2.5 Aiignmenf. The alignment of the die shall be maintained to prevent shift or pushover while under working pressure. 3.2.4.2.6 Finish. To insure accuracy and to eliminate soft skin due to decarburization in hardening, all cavities and guides shal
27、l have a No. 16 RMS or better. Where grinding is not prnctical the steel used shall be of a type MILT46398 (MU) which shall not change during the hafdenng process, beyond the allowable limits. Decar- burization shall be avoided and all working or wearing surfaces shali be stoned or polished. 3.2.5 T
28、ype V molding dies (for plastic and rubber parts.) 3.2.5.1 Hobbing method of die snking. Where powdered metal molding dies are used the hob produced shall be made of suitable tool steel, which after heat treatment shall possess high compression and transfer strength to resist splitting. The hob shal
29、l hold accurate size in hardening. 3.2.5.1 Machined molding dim. Where molding dies are produced by the machining process, the steel selected shall retain its accuracy after heat treatment and be able to take the required finish. 3.2.5.2 Design. Grade A dies shall be of the multiple cavity design. G
30、rade B dies shall be of the single cavity design. 3.2.5.2.1 Inserts. To facilitate maintenance, inserts may be used in the machined molded die provided they have sufficient reinforce- ment and are locked in place to prevent any movement detrimental to the die. They may also be used to overcome compl
31、icated heat treating conditions. They should not be used where their application would be detrimental to the die. 3.2.5.2.2 Sections. . To facilitate mainte- nance, accuracy, and machinability, sections may be used in the machined molding die provided they are properly installed and are not weakened
32、 by excessive use of screws and dowel pins. Sections lacking adequate sup port, backing, or conditions that would weaken the die should be avoided. 3.2.5.2.3 Vents. Vent size shall be sufficient to allow proper venting but shall not be ex- cessive to the extent that heavy flashes would result in an
33、excessive deburring operation. 3.2.5.2.4 Ejector. The ejector shall be the mechanical type. The activation of the ejec- tor shall be optional; air, hydraulic or mechanical. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NIL-T-4b378 12 = 7777706 03
34、11736 7 = MILT46398 (MU) 3.2.5.2.5 Alignment. The alignment of the die shall be maintained to prevent shift or pushover while under working pressure. 3.2.5.2.6 Fintkh. To insure accuracy and to eliminate soft skin to decarburization in hard- ening, all cavities and guides of the machined molding die
35、s and the hob shall have a No. 16 RMS finish or better. Where grinding is not practical, the steel used shall be of the type which shall not change during the hard- ening process, beyond the allowable limits. Decarburization shall be avoided and all work- ing or wearing surfaces shall be stoned or p
36、olished. 3.2.6 Type VI drill jigs Grade A and B. 3.2.6.1 Mate-. Drill jigs shall be made of iron castings which shall be of uniform quality and condition free from all defects such as cracks, porosity, hard spots, gasholes or foreign matter. The scale shall not be broken or disturbed where machine s
37、urfaces are not required. 3.2.6.2 Design. Grade A drill jigs shall be designed to drill all holes required in the piece on one cycle of operation. Grade B drill jigs will not be required to drill all holes in one cycle of operation but will require more than one set up or jig to drill all the requir
38、ed holes. 3.2.6.3 Construction. In forming four sides, two angle plates shall be used in lieu of four separate plates. Joining sections shall be flat machined or ground surfaces, attached with socket head screws and located with hard- ened dowel pins. The dowel pins shall be a force fit in the throu
39、gh holes and a slide fit in the blind holes. The slide fit of the dowel pins shall not be less than onediameter or more than two diameters in length. Holes shall be slightly countersunk to prevent false bearing on joining surfaces. Supports shall be added after machining where necessary. Care shall
40、be exercised to prevent the sup- ports from influencing the jig by setting up undue strain. 3.2.6.4 Alignment. The alignment of the jig shall be maintained to prevent shift during the drilling operation. 3.2.6.5 Combination of cast iron and steel. Drill jigs constructed of a combination of cast iron
41、 and steel are permitted provided they produce acceptable work. 3.2.6.6 Bushings. Bushings used in these drill jigs shall be made of hardened tool steel and have a lapped finish. 3.2.7 Type VII fixtures Grade A and B. 3.2.7.1 Matera. Fixtures shall be con- structed of suitable machine steel or iron
42、castings. Where machine steel is used, all wearing or bearing surfaces shall be hard- ened. Where castings are used they shall be made of iron of uniform quality and condition, free from all defects such as cracks, porosity, hard spots, gasholes or foreign matter. The scale shall not be broken or di
43、sturbed where machine surfaces are not required. 3.2.7.2 Design. Fixtures shall be designed to hold, locate and position the piece for the necessary machining operations. 3.2,7.2.1 Grade A. These fixtures shall be designed to permit machining from multiple settings by horizontal and/or vertical inde
44、x- ing. The fixture may also be designed as a multiple fixture permitting the same machin- ing operations on several pieces simultane- ously. Class A fixtures shall be automatically operated. 3.2.7.2.2 Grade B. These fixtures shall be designed to permit machining from one or more settings. Grade B f
45、ixtures shall be manually operated. 3.2.8 Tgpe VIII patterns Grade A and B. 3.2.8.1 Material. Grade A patterns shall be made of metal. Aluminum, bronze, cast iron or brass may be used. Grade B patterns shall be made of seasoned mahogany. 3.2.8.2 Design, Grade A and B patteiris shall be designed to p
46、roduce more than one casting in one complete cycle of operation. Due consideration shall be given to allow- ances for machining, shrinkage factors, and proper location of bosses and cored holes. 3.2.9 Tgpe IX manufactwing gages Grade A and B. 6 Provided by IHSNot for ResaleNo reproduction or network
47、ing permitted without license from IHS-,-,-MIL-T-Llb39 12 7999906 3.2.9.1 Mated. The material used in Grade A gages shall be a suitable machine steel. Bearing surfaces, wear plates and weai* points shall be made of either carboloy, chromium, tungsten, or diamond. Grade B gages shall be made of suita
48、ble machine steel. Bearing surfaces, wear plates, and wear points shall be made of high carbon steel. 3.2.9.2 Design. Grade A manufacturing gages shall be designed to measure more than one dimension at one time, with go and not go limitations. Grade B manufacturing gages shall be designed to measure
49、 a minimum of one dimension at one time wih go and not go limitations. 3.2.9.3 Accuracy. The tolerance of Grade A and 33 gages shall be equal to 10% of the tolerance specified by the part drawing. To insure compatibility, the gages shall meet the dimensions specified on the gage draw- ings. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for inspection. Unless otherwise specified in the contract or pur- chase order, the supplier is responsible for the performance of all inspection require- ments as specified
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