Advantages of soft machining

Soft machining is a machining process used in prototype manufacturing. It uses low cutting forces and low speeds to machine prototype parts to remove excess material. This technique is very beneficial for prototype parts and brittle materials that are difficult to machine with traditional methods, which are among the many materials used in marten machining.

1.Soft machining technology: precision and care

In soft machining, the total cutting depth of prototype parts with tight tolerances is obtained by cutting in multiple layers. Each layer has a different longitudinal overlap and lateral stepover. This reduces the forces and stresses during prototyping.

1) Milling: A versatile method for complex designs

Milling is mainly used in product development to remove excess material from the workpiece. It helps to transform the prototype part from the original shape to a specific shape.

Thus, parts with the required dimensions and tight tolerances can be created. This is an important step in the rapid prototyping of parts used in industries such as aviation, automotive, and medical, which require tight tolerances in the final product development.

In full-scale production that requires batch or mass production, cost-effectiveness is considered the most important parameter.

It also provides a highly polished surface finish and can create complex 3D parts. It allows for mass production or batch production, which is difficult to achieve with other machining processes.

Milling CNC machining can produce identical parts with tight tolerances repeatedly and in large batches and mass production. Milling can be applied to all types of materials such as metals, alloys, plastics and polymers, etc.

2) Turning: Precision machining of cylindrical and rotating parts

Turning is the process of creating a specific shape of raw material by rotating the workpiece and moving the cutting tool in a linear direction. This will form a cylindrical shape.

Turning is usually done using a lathe. Turning of prototype parts can be done both automatically and manually. Manual turning requires constant supervision. Automatic turning is an effective process for batch and mass production.

By using CNC machining methods, all parameters such as speed, cutting force and production tools can be programmed by computer. CNC machining allows the creation of workpiece shapes with high precision and tight tolerances in a consistent and efficient process in full production.

Single point tools of different shapes are used when turning soft tools. Different angles are used for adjustment to obtain the desired shape.

3) Drilling: Precise and controlled drilling of holes

Drilling is the process of creating a circular hole in a workpiece. Drilling machines can be used for milling machines. Chips are generated as waste. The drill bit is designed in such a way that the chips fall off the workpiece. The workpiece remains chip-free.

During prototyping, keeping the drill bit vertical reduces deflection and deviation. To ensure tolerance, the center drilling process is done before drilling. Other drilling methods in soft machining are head rotation on manual machines and multi-axis on CNC machining.

4) Grinding: Achieving ultra-fine surface finish and tight tolerances

Grinding is the process of creating the final shape of a workpiece by removing excess material through abrasion. In mass production, rotating grinding wheels are used to shape materials through grinding.

Soft machining processes utilize abrasive particles to remove material from the surface of prototype parts with tight tolerances. When the prototype part comes into contact with the moving abrasive particles, the abrasive particles act as tiny cutting tools. This shears off all the small chip particles in the rapid prototype from the workpiece.

There is a misunderstanding about grinding in mass production. It is the process of rubbing the material with an abrasive grinding wheel. However, it has the same cutting action as milling, tuning, and drilling in product development.

2.Materials suitable for soft machining: delicate and diverse

Both manual soft machining and CNC machining can process any type of material in mass production with tight tolerances. These materials include plastics, alloys, composites, and nonferrous metals.

1) Plastics: a versatile and moldable field

Plastic soft machining is an important application area for CNC machining. Plastics can be soft machined according to their specifications and characteristics. Plastics have poor thermal conductivity. Therefore, it is very important to remove the heat generated by chips during plastic machining.

Plastic prototype parts are cast or drawn. Soft machining such as grinding, milling, turning, and drilling can all be used for plastics.

But machining plastics requires sharp cutting tools with very smooth surfaces. This can quickly separate the plastic and remove it effortlessly. This can achieve a smooth surface finish for prototype parts in product development.

① Types of plastics suitable for soft machining

The types of plastics that can be machined are:

1. Thermosetting plastics: epoxy resin, formaldehyde resin, polyurethane, silicone rubber
2. Thermoplastics: Polyethylene, Polypropylene, Polyvinyl Chloride, Polytetrafluoroethylene, Polyvinylidene Fluoride, Polyester, Polyamide
3. Elastomers: Rubber, Latex
4. Fibers: GF, CF, AFU
5. Foams: PE, PU Soft Foam and Hard Foam

2) Composites: Mixing Strength and Lightweight Properties

Soft machining of composites is the shaping and finishing of prototype parts through cutting, milling, adjustment, drilling and other processes. Composite machining requires special tools and methods because they are hard and layered materials.

Composite machining helps to shape with tight tolerances during prototyping while maintaining the integrity of the material. Soft machining helps rods and tubes fit accurately and form a perfect combination in rapid prototyping.

3) Non-ferrous Metals: Achieving Precision and Beauty

Non-ferrous metals do not contain iron and are excellent machinable materials. They are easy to cut, drill, turn and grind. They have a smooth surface and are cost-effective. High electrical and thermal conductivity are ideal for machining prototype parts.

Surface treatment processes such as anodizing also produce better results after machining non-ferrous metals. Lightweight metals reduce the overall weight in the prototyping process and product development.

3.Soft machining tools

Soft tools are used to create temporary molds in production methods. Soft tools made of easy materials are used in rapid prototyping and initial manufacturing stages such as prototyping processes.

In mass production of product development, it precedes durable and expensive hard tools. Soft tools are more cost-effective in production tools.

Another advantage of soft tools is the flexibility of material requirements. It increases the convenience and versatility of production tools. Soft tools are conducive to rapid prototyping before mass production and mass production.

1) Examples of soft machining tools

The soft tools used in the process of creating prototype parts are as follows:

1. Silicone molds: Since they are affordable and easy to manufacture, they can be used to create prototype parts as well as small batch production and large-scale production.
2. Carbon fiber: These molds are cost-effective and durable. They are suitable for small batch production and rapid prototyping of precision parts.
3. Fiberglass: This choice also has great cost-effective advantages for large parts and prototype parts. But additional finishing is required to obtain a smooth surface.
4. Aluminum Tooling: This is the expensive option among soft tooling. It has high durability and better heat transfer rate in batch and high-volume production.

4.Applications of Soft Machining: Industry and Product Range

Soft machining is well suited for manufacturing complex parts that require high precision and high tolerances, as described below:

1) Aerospace: Precision and performance in harsh environments

Notable applications of soft machining (whether manual or CNC machining) include the manufacturing of cabin components, wing ribs, and fuselage components. CNC machining is also used to manufacture actuators, motion control sensors, engine casings, landing gear components, and tray and filter bodies.

2) Medical: Precision life-saving devices

Soft machining is widely used in the medical field due to its high precision, tight tolerances, flexibility and versatility. These applications include rapid prototyping of medical device parts, manufacturing of orthopedic implants for hip and knee replacements.

It is also used to manufacture surgical instruments and endoscopic tools, and to manufacture parts for diagnostic equipment.

3) Electronics: Miniaturization and performance of cutting-edge devices

The main example of soft machining in electronics is the metal alloy casings of Apple products. These casings are made by CNC machining and CNC routers.

It is also used in products such as PCBs, casings, fixtures, semiconductor devices such as wafer plates, gas distribution channels, wafer carriers, and solder flex templates.

4) Consumer products: Aesthetics and functionality of everyday items

Soft machining is used in niche manufacturing industries such as jewelry, musical instruments, furniture, consumer electronics, and semiconductors. These industries include manufacturing pianos, engraving, carving, tuning knobs, fret slots, and other musical instruments. Metal frames, glass cutting, polishing, and furniture carving.

5.Soft machining: A winning combination of fine materials

1) Minimize material removal and reduce stress

Using material removal methods, incomplete castings can be manufactured to meet design specifications. This can turn ordinary castings into unique finished products.

Soft machining has this advantage while also reducing stress. These stresses are caused by thermomechanical and chemical factors during the machining process and can cause fatigue failure.

2) High Precision and Tight Tolerances

Tight tolerances are allowed, with a variation range of 0.005 inches. Soft machining can produce parts with high precision and tight tolerances, and the actual size deviation of the prototype part may not exceed 3 inches.

3) Smooth Surface and Reduced Burrs

Soft machining re-grades the surface finish best and produces the smoothest surface finish, which can be attributed to many factors. These factors include material elasticity, demolding characteristics, vibration reduction, and fewer tool marks (unlike hard machining).

4) Applicable to a variety of materials and geometries

Soft machining excels in processing complex parts. It has flexibility in the machining process and can create delicate shapes with higher precision and tight tolerances. Soft machining can create 3D parts that are highly realistic to the model. It also has fast turnaround and cost-effectiveness.

6.Challenges and Considerations in Soft Machining: Ensuring Successful Machining of Precision Materials

1) Tool Selection and Optimization

Soft machining tools have poor durability, wear and deformation are faster under high pressure and high temperature conditions, shorten tool life, frequent replacement, and increase production costs, so tool optimization and selection are important factors in soft machining.

2) Process Planning and Optimization

Soft machining processes have longer cycle times. The flexibility of the process may require additional demolding, cooling or setup time, which may affect the efficiency of the project.

3) Fixtures and Workholding

Soft molds and materials may experience machining and fixturing problems. This occurs due to insufficient clamping force and pressure applied to the workpiece. This causes the workpiece to move, slide and deform.

4) Cooling and Lubrication

Efficient cooling and lubrication can extend the life of production tools, shorten machining cycles, improve the performance of product development processes and improve surface quality.

5) Monitoring and Control

Reliable monitoring and control provide real-time insight into the process. This can improve the entire production development process in the long term. Monitoring of machines and processes reduces the likelihood of abnormalities and ensures high productivity. This can be challenging in soft machining processes because of the higher process flexibility and longer process cycles.

7.Advantages and Disadvantages of Soft Machining

1) The advantages of soft machining are as follows:

1. Fast Turnaround: This process makes it easy to shape and modify prototype parts. It also allows for rapid design iterations and adjustments in product development.
2. Cost-effectiveness: It can be performed at low to medium batch production rates. Soft machining uses cheaper materials than hard machining and is suitable for low-budget projects.
3. Complex and delicate geometries: It has higher flexibility in handling complex designs and can form geometries with tight tolerances very accurately. It can also create products with

2) Disadvantages of soft machining are as follows:

1. Small batch production vs. large batch production: It is suitable for low- and medium-volume production and cannot withstand large-scale high-volume demand.
2. Limited mold life: Soft molds have poor durability and require frequent replacement and repair. This sometimes also increases production costs.

8.Conclusion: Soft machining – an indispensable tool for precision material processing

Soft machining is used for design verification, product testing, and small batch production. It is suitable for prototyping processes or testing designs before mass production. It is the first choice for creating complex designs that may be time-consuming and challenging for hard machining.

The advantages of soft machining are cost-effectiveness, high surface finish, fast turnaround, design and process flexibility, and manufacturing of complex geometries. However, due to low production volume, it has some limitations and is not suitable for large-scale production.