Tips for Machining Mechanical Parts

Tip 1: There is a common practice of first positioning and then clamping when machining workpieces; however, for a single workpiece, it is better to clamp first and then position. This is because clamping inevitably causes deformation of the workpiece, so clamping should be done before positioning. In the case of the six-point positioning system, the goal is to constrain the degrees of freedom of the workpiece.

Tip 2: Use a magnet to pick up small parts. Since both picking up and retrieving such parts can be inconvenient, you can attach an iron plate (2) beneath magnet (1). Not only can this setup hold many small parts, but when you pull the iron plate away, the parts will instantly and automatically fall into the collection bin—practical, if not exactly thrilling!

Tip 3: When using belt drives, the belt often slips on the pulley. To prevent this, use a 15–18 mm countersink bit to cut a series of recesses into the pulley hub. This creates an adhesive effect that reduces slippage—turning waste into a useful feature that your boss will surely appreciate!

Tip 4: When the hex key has a short shank and insufficient leverage, insert a tube with an inner diameter slightly larger than that of the key into a milled groove on the key’s shank to effectively extend the handle.

Tip 5: Remove the jaws of the vise and machine two M4 threaded holes. Then, rivet two 1.5-mm-thick steel plates—flush with the jaw surface—using aluminum countersunk rivets to secure a 0.8-mm-thick hard brass plate. Finally, fasten this assembly to the vise jaws with M4 countersunk screws, creating a durable soft jaw. This approach also protects hardware components from being damaged by clamping and ensures interchangeability.

The selection of various cutting parameters must adhere to established principles when balancing cutting speed and machining quality. Operating at speeds exceeding the specified limits or at excessively high spindle speeds can lead to elevated cutting temperatures, increased centrifugal forces on the workpiece, and potential machine tool vibration. As spindle speed increases, the outward tensile force exerted on the workpiece by the rotating spindle also increases; this effect is particularly pronounced during finish machining, where centrifugal forces significantly impact the spindle bearings.

1. Conduct a detailed review of the product assembly drawing and part drawings, and perform process analysis on machined parts.

2. Integrate the necessary heat treatment operations into the machining process sequence to fully maximize the effectiveness of heat treatment.

3. Complete process documentation, etc.

4. Formulate the process route, select the positioning datum, determine the machining methods, divide the machining stages, arrange the machining sequence, and decide the content of each operation, among other tasks.

5. Select and confirm the machine tools, cutting tools, fixtures, measuring instruments, and auxiliary tools to be used in each machining operation.

6. Determine the machining allowances, process dimensions, and tolerances for each operation; and specify the technical requirements for the primary operations or prepare simplified process diagrams.

7. Determine the cutting parameters, worker skill level, and standard work hours.

8. Determine the technical requirements and inspection methods for the primary processes.

Trend of Miniaturization in Mechanical Components

With the advancement of mechanical technology, miniaturization has become the primary trend in the development of contemporary mechanical components. Micro- and nano-scale devices that integrate mechanics, electronics, control systems, and information technology—represented by MEMS—are a key direction in modern mechanical engineering.

Based on feature size, micro- and miniaturized machines can be classified into three major categories: small-scale machines (overall dimensions between 1 mm and 10 mm), microscale machines (overall dimensions between 1 μm and 1 mm), and nanoscale machines (overall dimensions between 1 nm and 1 μm).

Due to their small size, light weight, and compact structure, micro- and miniaturized machines are widely used in fields such as information technology, automotive engineering, bioengineering, and aerospace, making them a key area of development for countries around the world.

Micro-machining refers to a machining technique in which material is directly removed from the workpiece by mechanical forces applied through high-resolution solid tools on precision and ultra-precision machine tools. Among these, micro-turning and micro-milling are the most commonly used processes.

In the mechanical manufacturing and machining industry, turning is one of the most widely used machining processes, and micro-turning is a subset of turning. The general principles governing conventional turning also apply to micro-turning; however, in addition to inheriting the characteristics of conventional turning, micro-turning offers distinct advantages when machining miniature tubular components and small-diameter shafts. Furthermore, the selection of cutting parameters in micro-turning has its own unique features, particularly with regard to the dynamic characteristics of the cutting system. For instance, the cutting speed is often chosen at a relatively low spindle speed to accommodate the dynamic performance of the machine tool, as this has a greater impact on the surface quality of the workpiece. To further enhance surface quality, the depth of cut is carefully optimized.

Higher spindle speeds lead to greater machine-tool vibration; therefore, ultra-precision turning typically employs very small feed rates. Milling, by contrast, is a relatively flexible machining process. Micro-milling is a versatile method for fabricating micro-components and complex three-dimensional structures from a wide range of materials, and it has become the preferred approach for producing miniature, intricately shaped 3D parts with diverse material options. Moreover, it is one of the principal manufacturing technologies for realizing micron-scale and intermediate-scale mechanical devices and components. When used for machining miniature parts, micro-milling offers high flexibility and speed, while also featuring moderate machining costs, competitive production rates, and a well-established body of supporting foundational technologies.