As an important part of the spacecraft thermal control protection system, the thermal control coating is like the skin of the human body, protecting the spacecraft from operating in various complex space environments.It is of great significance to ensure the normal operation of various parts and structures inside the spacecraft.
The performance of the thermal control coating mainly depends on the surface characteristics of the coating. The most important parameters are the solar absorption ratio αs and the hemispheric emission rate £H.Each material has a specific solar absorption ratio and hemispherical emissivity, and theoretically can be applied to a certain thermal environment to achieve a certain thermal control function.But the actual situation is: a single material often cannot meet the design requirements of spacecraft in terms of heat radiation performance, mechanical properties, specific gravity, and cost.For example, aluminum alloy is the most commonly used material in spacecraft. It has the advantages of low specific gravity, high strength, and relatively low cost. However, in some parts of stars and ships, the heat radiation performance of aluminum alloy cannot meet the demand.From the comprehensive consideration of thermal performance, mechanical performance, cost and other aspects, the best solution is to cover the surface with a layer of material with the required thermal radiation performance, that is, a thermal control coating, so as to achieve a balanced combination of multiple properties.
Example . Small sleeve
1.Material: 45 steel. 2.Hole and external round chamfer C1. 3.Quenching 30~35HRC. 4.Blue treatment.
1.Part drawing analysis
1）The part material is 45 steel.
2）Quenching 30 ~ 35HRC.
4）The coaxiality tolerance of ϕ57 + 0.05 outer circle and ϕ40 + 0.025 inner hole is ϕ 0. 01mm.
To ensure that the coaxiality tolerance of ϕ57 + 0.05 outer circle and ϕ40 + 0.025 inner hole is ϕ 0. 01mm, the machined parts
At this time, it is necessary to turn and machine ϕ57 + 0.05 outer circle and ϕ40 + 0.025 inner hole after clamping once.
sleeves Machining process
|Part Name||Blank species||Material||Production type|
|Small sleeve||Round steel||45 # steel||Small batch|
|Process||Work step||Process content||Equipment||Tools, measuring tools, auxiliary tools|
|10||Blanking ϕ 75 × 120||Sawing machine|
|20||Rough turning||Horizontal lathe|
|1||Use the self-centering chuck to clamp the outer circle of the blank, align, clamp, turn the end face, and turn it flat.||45° elbow turning tool|
|2||Drill ϕ20 hole to ϕ19 through hole||ϕ19 Twist group|
|3||Boringϕ40 ＋ 0. 025hole to ϕ38, depth 84||Closed hole boring tool|
|4||Turning ϕ57 + 0. 052 outer circle to ϕ59, as long as ϕ70 to the end face, leaving a margin of 1||90° external turning tool|
|5||Turning ϕ55 outer circle to size ϕ57, length to ϕ57 + 0. 052 end face||90° external turning tool|
|6||Turn around. Use a self-centering chuck to clamp the outer circle of ϕ55, align, clamp, and turn the outer circle of ϕ70 to ϕ72||90° external turning tool|
|7||Turning the left end face completed||45° elbow turning tool|
|30||Heat treatment: quenching 30 ～ 35HRC||Salt bath furnace|
|40||Fine turning||CNC lathe|
|1||Use the self-centering chuck clamp ϕ70 to align, clamp, and turn the end face at the outer circle to keep the total length and allowance 1||45° elbow turning tool|
|2||Semi-finished turning ϕ57 + 0.052 outer circle to 57.8, as long as ϕ70 end face, flat end face to the requirements||90° external turning tool|
|3||Turning ϕ55 outer circle to the requirement, guaranteed length 55||90° external turning tool|
|4||Finish turning ϕ57 + 0. 052 outer circle to the requirements, guaranteed size 50, surface roughness Ra0. 8μm||90° external turning tool|
|5||Boring ϕ40 + 0.025 inner hole to ϕ39.2, depth 85||Closed hole boring tool|
|6||Turning inner hole slot 4 × 1||Internal groove turning tool|
|7||Fine boring ϕ40 + 0.025 inner hole to request, depth 81, surface roughness Ra0. 8μm||Fine Boring Tool|
|8||Face chamfer C1||45° elbow turning tool|
|9||Turn around. Use self-centering chuck clamp ϕ55 to align the outer circle, clamp, and turn the end face to ensure the total length 115||45° elbow turning tool|
|10||Turning ϕ70 outer circle to requirement||45° elbow turning tool|
|11||Boring ϕ20 holes to requirements||Boring tool|
|12||Turning hole chamfer C1||45° elbow turning tool|
|60||Heat treatment: bluing treatment|
|70||wrap up and warehousing||Warehouse|