NUMERICAL CONTROL UNITS

TM 38-260

4-25. NUMERICAL CONTROL UNITS

a. Numerical controls. Numerically controlled machine tools, while having their own unique features, can be

processed in the same manner as prescribed for conventional machine tools. Numerically controlled machine tool

controls are generally referred to as Machine Control Units (MCUs).

b. Components. Components of MCUs are relatively light weight, as compared to the more massive and bulky

components of the machines themselves, and, except for earlier models, are almost exclusively solid state devices.

(1) Insulation from vibratory loadings is of paramount importance to the entire MCU (which may be of

considerable cubage and weight).

(2) It is imperative that the mechanical security of a MCU be assessed initially for internal requirements

(component cards, power supplies, loaded shelving, and tape readers, when applicable) and then for the application of

boxing or crating, skidding, environmental barriers, vibration dampening materials placement, and other physical security

measures.

(3) In addition to the preservation, packaging, and packing requirements contained in MIL-E-17555, the

following detailed requirements are applicable when preparing numerically controlled machine tools for shipment.

(a) The assembled units shall be processed using only those cleaning processes that will not damage

delicate systems and materials.

(b) Solvent cleaning shall not be used in the cleaning of electrical or electronic circuitry.

be used for cleaning.

(d) No further cleaning or preservation is required.

(4) Electron tubes shall be processed in accordance with k. below.

c. Cushioning, blocking, and bracing. Cushioning, blocking, and bracing of MCU shall be in accordance with MIL-

STD- 1186 and military specification MIL-E- 17555.

(1) Foam-in-place packing procedures. IPE, accessories, and component parts may be blocked, braced, and

cushioned in accordance with the foam-in-place packing procedures of MIL-STD-1191.

(2) Heavy items, such as transformers, power supplies, and amplifier assemblies especially if shelf mounted,

shall be blocked and braced to prevent dislodgment or failure of the supporting structure(s) throughout the

transit/handling period.

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