TASK 70-16-00-350-001
1 . General.
A.Identification of parts, assemblies, subassemblies, modules and/or engines is achieved by marking at the time of manufacture. The type and location of marking is determined by the size, shape, material, environment, function, etc., of the part.
B.There are two categories of marking: permanent and temporary.
(1)Permanent marking normally will imprint the part with the required information and is intended to remain legible through engine operation and maintenance procedures.
(2)Temporary marking is accomplished by applying or adding some material to the surface of the part. Temporary marking is not intended to withstand engine operation and is normally removed during or following maintenance procedures.
C.Many engine parts are exposed to high temperature environments during use or maintenance. Improper marking may be obliterated by high temperature and the part identification lost. Chemical attack from marking materials exposed to high temperature may corrode the part and lead to possible part failure.
D.Some marking methods require deep impressions in the part, causing local stresses. The use of these marking methods must be carefully considered relative to the tolerance of the part to these stresses. These marking methods are the most permanent, however, and are frequently utilized.
2 . Permanent Marking.
Subtask 70-16-00-350-011
A.Permanent marking of part is often required when parts are modified during maintenance and the part identification is changed. Permanent marking may also be used to monitor part life or history.
B.The method and location of permanent marking must be selected so as not to cause damage to the part.
C.Application: Typical uses for permanent marking are:
(1)Part number identification change following a modification of the part.
(2)Indicate compliance to service bulletins.
(3)Indicate repairs completed.
(4)Indicate the number of heat treat cycles on part.
(5)Indicate the accumulated hours or cycles on part.
(6)Indicate position marking for aid in assembly.
D.Marking Methods: Whenever permanent marking is required, the method and location are usually specified in the Engine/Shop Manual. When marking instructions are not specified or the method and/or location is not available, the following recommendations should be followed.
(1)Mark in low-stress areas.
(2)Do not mark on any surface which contacts another surface during assembly or operation such as flange mating surfaces or other areas subject to possible contact or wear.
(3)Do not mark on surfaces exposed to the primary gas flow of the engine.
(4)Do not remove or totally obliterate existing markings, but line-out or mark through existing marking such that it remains legible.
(5)Make new marking adjacent to, or in the same area as existing marking.
(6)Make new marking on the same surface as existing marking.
(7)Make new marking by the same method and same size characters as the existing marking.
(8)Do not use impression type marking which could cause deformation of part or reduced wall thickness on thin walled parts.
(9)Do not use impression type marking on parts made from titanium alloy.
3 . Temporary Marking.
Subtask 70-16-00-350-012
A.Temporary marking is used for temporary identification purposes. This is accomplished by the attachment of tags or adhesive labels or marking directly on the part. Temporary marking is usually removed prior to assembly or operation of the engine. The materials selected, however, should be chosen so that failure to remove the marking will not cause damage or failure of the parts so marked.
(1)Application: Typical uses for temporary marking are:
(a)Indicating location of defects during inspection.
(b)Indicating relative position of parts in an assembly by sequential numbering or matchmarks.
(c)Identifying the subassembly, module, or engine the part may be assigned to or removed from.
(d)Identify shop operations or inspections performed or to be performed.
(2)Marking Methods: Whenever temporary marking is required, the method and location are usually specified in the Engine/Shop Manual. When marking instructions are not specified or the method and/or location not available, the following recommendations should be followed:
(a)Metal tags must be made from stainless steel and held to part with stainless steel wire.
(b)Adhesive on tape or labels must be approved by suitability tests to ensure against corrosion to parts when subjected to high temperature.
(c)Marking ink, pencils, paints, etc., must be approved by suitability test to ensure against corrosion to parts when subjected to high temperature.