ME3031 - Machine Manufacturing Technology (Công nghệ Chế tạo Máy)

Comprehensive English vocabulary flashcards covering the manufacturing engineering lecture questions ME3031 (ĐHBKHN), spanning operational organization, surface integrity, machining precision, and fixturing/datums.

Operation Decentralization (Phân tán nguyên công)

A technological organization method where the manufacturing process is split into multiple small operations, each performed on a single standard machine tool.

Operation Centralization (Tập trung nguyên công)

A manufacturing method commonly applied to complex parts with numerous surfaces requiring machining on multi-spindle modular machine tools, characterized by complex machine setup.

Production Type (Dạng sản xuất)

The organizational scale of production (single-piece, batch, or mass production) determined fundamentally by the annual production volume and the weight of the part.

Superficial Rockwell Hardness Test

A surface hardness testing method using a $120^\circ$ diamond cone or a steel ball indenter, where hardness is determined by the impression depth difference between major and minor loads after elastic recovery.

X-Ray Method (Phương pháp tia Rơnghen)

A non-destructive testing method used to evaluate and measure internal residual stresses and the depth of the work-hardened surface layer, though it is complex and time-consuming.

Surface Quality Criteria

The comprehensive technical characteristics of a machined surface, encompassing surface roughness, surface waviness, and the physical-mechanical properties of the superficial layer.

Work Hardening (Biến cứng bề mặt)

An increase in the superficial hardness of a machined part caused by crystal lattice deformation under plastic deformation induced by cutting forces.

Economic Machining Accuracy (Độ chính xác kinh tế)

The machining accuracy achievable under normal, standard production conditions at the minimum manufacturing cost.

Technological System Stiffness ($j$)

A measure of resistance to deformation on a force-deformation ($P - y$) plot, quantitatively determined by the tangent value $\tan(\alpha)$ of the tangent line drawn at an operating point on the curve.

Geometric Form Errors (Sai số hình dáng hình học)

Deviations in the ideal geometry of a part profile, specifically including taper (độ côn), ovality (độ ovan), barrel shape (độ tang trống), and lobing/polygonal form (độ đa cạnh).

Datum (Chuẩn)

A collection of surfaces, lines, or points used to determine the relative spatial position of other geometric elements or components during design, manufacture, or inspection.

Rough Datum (Chuẩn thô)

A locating datum chosen on a raw surface that has not undergone any prior mechanical cutting, which should critically be utilized only once in the initial machining operation.

Unified Fine Datum (Chuẩn tinh thống nhất)

A previously machined locating datum surface utilized consistently across the majority of subsequent machining operations throughout the entire technological manufacturing sequence.

Datum Error ($\varepsilon_c$)

The machining error produced when the positioning datum fails to coincide with the design (dimensioning) datum; it is identically zero when the locating and design datums coincide.

Fixturing Error ($\varepsilon_{gd}$)

The vector combination of datum error ($\varepsilon_c$), clamping error ($\varepsilon_k$), and fixture error ($\varepsilon_{dg}$), given by $\varepsilon_{gd} = \sqrt{\varepsilon_c^2 + \varepsilon_k^2 + \varepsilon_{dg}^2}$, usually specified as $(1/3 \sim 1/5)\,\delta_{nc}$.

Fixture Manufacturing Error ($\varepsilon_{ct}$)

The allowable manufacturing tolerance of a fixture derived from the fixturing error: $\varepsilon_{ct} = \sqrt{\varepsilon_{gd}^2 - (\varepsilon_c^2 + \varepsilon_k^2 + \varepsilon_m^2 + \varepsilon_{dc}^2)}$, requiring the radicand to be strictly positive.

Fixture Adjustment Error ($\varepsilon_{dc}$)

The empirical error range occurring during setup and adjustment of the fixture on the machine table, typically valued between $5 \sim 10\,\mu\text{m}$.

Technological Step (Bước công nghệ)

A distinct part of an operation dedicated to machining a single surface using a single tool (or fixed set of tools) under unvarying cutting parameters.

Workpiece Clamping Setup (Gá)

A single continuous positioning and clamping event of a workpiece in a fixture to execute a portion or the entirety of an operation.

Basic Machining Time ($T_o$)

The primary cutting duration during which the dimensions, shape, or state of the workpiece are directly and actively modified by the cutting tool.

Production Tact Time / Rhythm (Nhịp sản xuất)

The fixed time interval required for the periodic completion and output of one finished product unit on a mass-production line.

Profile Roughness Parameter $R_a$

The arithmetical mean deviation of the assessed surface profile within a defined sampling length.

Profile Roughness Parameter $R_z$

The average height difference between the five highest peaks and five deepest valleys within the designated evaluation length of the profile.

Built-Up Edge (Lẹo dao - BUE)

Highly strain-hardened workpiece material adhered to the tool rake face near the cutting edge, occurring predominantly at intermediate cutting speeds ($V \approx 15 \sim 30\,\text{m/min}$).

Surface Burnishing (Lăn ép bề mặt)

A chipless surface-finishing process using rollers to deform micro-asperities plastically, smoothing out surface roughness and imparting compressive residual stresses.

Shot Peening (Phun bi thép)

A mechanical surface enhancement process blasting steel shots against the surface to create plastic deformation and deep compressive residual stresses, significantly extending fatigue life.

Surface Waviness (Sóng bề mặt)

Intermediate periodic surface undulations possessing wavelengths larger than micro-surface roughness ($R_a$) but smaller than macroscopic geometric form errors.

Error Copying (Hiện tượng in dập sai số)

The transmission of initial raw blank form errors (such as ovality) onto the machined surface as a direct consequence of elastic deflections in the technological system under variable cutting depths.

Six-Point Locating Principle (Nguyên tắc 6 điểm)

The fundamental fixturing principle stating that any rigid spatial body possesses a maximum of six independent degrees of freedom that can be constrained using six locating points.

Hyperstatic Fixturing / Over-Constraining (Siêu định vị)

An erroneous locating condition in which one or more spatial degrees of freedom of a workpiece are redundantly constrained by multiple locating elements, risking distortion and inaccurate clamping.

Short V-Block (Khối V ngắn)

A standard prismatic fixturing locator with a short axial contact length designed to locate cylindrical workpieces while constraining exactly $2$ translational degrees of freedom.

Machining Allowance (Lượng dư gia công)

The intentional layer of metal removed from a blank during machining passes to achieve the design dimensions, geometry, and surface integrity specifications.

Gaussian Dispersion Limit ($6\sigma$)

The total statistical scatter band encompassing approximately $99.73\%$ of all parts machined in a stable random process; if the dimensional tolerance $T < 6\sigma$, scrap parts inevitably occur.

Grinding Burn (Hiện tượng cháy xém khi mài)

Thermal damage accompanied by microstructural alteration and localized softening on a ground surface, caused by high frictional temperatures (up to $\sim 1000^\circ\text{C}$) generated by abrasive grains.

Self-Excited Vibration / Chatter (Rung động tự kích)

Unstable, dynamic vibrations generated directly by the cutting mechanics itself, mitigated by improving fixture/toolholder rigidity, applying tuned dampers, or modifying cutting speeds and feeds.