My Milling Machines

Micro milling is one of the three common micro cutting techniques used in micro machining.

In micro milling, the tool bit with diameter as small as 0.1mm is held in a high speed spindle rotating at 20,000 to 150,000 rpm, and used to mill steel, brass and aluminum with depth of cut at about 30 microns and feed rates of 120mm/m to 240mm/m to provide surface quality finishes as good as 0.2 microns.

While micro milling has been successfully applied in manufacturing bio-medical components, embossing dies and micro encoders, the breakage of the tool bit has been identified by many users as a teething problem.

Why does the tool bit break so easily in micro milling as compared to conventional milling?

There are 3 main reasons:

Firstly, when metal is removed by machining, there is a substantial increase in the specific energy required as the chip thickness decreases. This means that in the case of micro machining, as the chip gets thinner with smaller depths of cut, the micro tool bit will be subject to greater resistance when compared to conventional machining. It is as if the workpiece material becomes harder during micro machining. This resistance force is strong enough to exceed the bending strength limit of the tool bit even before the tool experiences any significant wear, and leads to the breakage of the tool bit. One way to prevent this is to make the chip thickness smaller than the edge radius of the tool bit.

Secondly, a sharp increase in cutting forces and stress from chip clogging during the micro milling process would cause the tool bit to break. In most micro milling operations using miniature micro tool bit with two cutting edges, each cutting edge removes the chips from the machining area only within half a rotation. However, if chip clogging occurs, the cutting forces and stresses will increase beyond the bending strength limit of the tool bit within a few tool rotations, and the tool bit will break. Some users prefer high speed steel tool bits as these are very much more flexible and tolerate clogging better than carbide tool bits.

Thirdly, the tool bit tends to lose its cutting edge due to built-up edge and cannot machine efficiently. As the workpiece starts to push on the tip of the tool bit, the tool bit will deflect slightly. The increase in tool deflection and the stress generated by the milling with every rotation will eventually cause the breakage of the tool bit. This process is also called extensive stress-related breakage.

In view of the above phenomena occurring in micro milling, most micro milling machines are sold with sensors to measure the forces acting on the tool bit, and advanced CAM software to predict the chip load throughout the micro machining process. In this way, precision manufacturers seeking a niche in micro milling could try to keep their machines running smoothly with minimal machine downtime.

About the Author

Author Ken Yap is a director of Suwa Precision Engineering Pte Ltd in Singapore and represents precision component manufacturers from Suwa, also called "The Oriental Switzerland" in Japan due to its Swiss resemblance for rich watch-making industry, its mountainous terrain and its precision component making industry.

Author Ken Yap

A CNC Rotary table is a piece of CNC milling equipment used for precision metalworking. It is similar than a dividing head or indexing head except that it is fixed to be used in only two planes, the horizontal plane and the vertical plane. A CNC Rotary table is used for CNC milling and is made up of a solid base that has proper provisions for clamping metal material on tables and other kinds of equipment. The table of this CNC milling equipment is a precision machined disc that also has provision to clamp materials in it, that is aided with a T slot. This CNC milling equipment can rotate by itself or be controlled by a worm or a handheld operational control.

1. Extreme Accuracy

A graduated dial and a vernier scale allow this rotary table to be positioned to a high degree of accuracy. The center of CNC milling equipment has hole that allows a morse taper center or fixture to be inserted. A tailstock is usually provided if the rotary table can be mounted from its end, so that the axis will be horizontal. The most common use of this CNC milling equipment is on it vertical axis that in this mode is on the same plane as the cutter when it is used on a milling machine.

2. Coaxial Design

If the CNC rotary table is mounted on a secondary table the work piece is adjusted in the center around the rotary tables axis, in this position the work piece is centered around the cutting tools axis; this make all three axis coaxial. Making a way for the secondary table to be offset in either the x or y plane so that the cutter is pitched at a distance from the work piece’s center allowing a simultaneous operations on the work piece.

3. Specialized Or General?

There are literally hundreds of CNC milling equipments available on the market today with different specifications and different additional features. They come in all types of shapes and sizes. Some are designed for specific applications, while others are more of general purposes in nature. When looking for the right CNC rotary tables, try to talk to people who already using this kind of equipments from them you can learn how this things work. The good thing about talking to this people is that you will gain information not based on industrial propagandas but on experience and uses of there CNC milling equipments. You can also visit a shop in your area so that you will ly see on how CNC rotary tables work. You can eve try to use one CNC milling equipment to know how it feels. You can also attend CNC seminars to be able to gain professional views about his matters and also do not forget to check online information sites.

4. Setting Up Shop

When setting up your CNC rotary tables make sure that the platform is stable and your CNC milling machine secure. Setting up your CNC milling machines is a critical issue to early success, the less movement that occur the better. The right material to be used should also be thought about when using this kind of CNC milling machines. Determine the right thickness and sizes of your materials. Also look for proper fixtures for your CNC milling machines, for this will save time, money and frustration when using your CNC rotary tables.

Before going into production, make a plan to test the different variables you need to work with for a period of time. Getting familiar with your machine is also a critical issue for success. Try to make familiar with the different types of cut, type of materials to be cut, the table type, the depths of cut, the feed rates and the type and sizes of bits that you will be utilizing. Feel around the machine but not literally though for it may I injure you.

5. Satefy

Make sure to read your manuals and have a thorough understanding about the safety measures and the different features of your CNC milling machines. Have a good idea on how this things works. On what it can do to make your business prosper and also on how it can harm your employees.

About the Author

For more great cnc rotary table related articles and resources check out http://www.onlyrotary.com

Author Mark Jansen

High speed machining is a proven stipulation characterized by low cutting forces and high metal removal. High Speed Milling is a technique used in the CNC Milling

Industry that combines high spindle speeds with increased feed rates. This results in a high chip-forming rate and lower milling forces, producing an improved surface quality and closer tolerances. In high speed milling, the electronics can make all the difference. The right CNC coupled with other elements of the control system can let a slower machine mill a given form faster than a machine with a higher top feed rate.

1. High Speed Uses

High-speed CNC milling is used, for example, to machine the titanium rotors of the first high-pressure compressor stages of the EJ200 engine. High speed CNC milling allows cost-effective milling of the airfoil geometry from the solid. By subsequent finishing operations the planned surface finish is achieved. The CNC milling which caters to high speed must be structured with an axis movement system that is suitable for machining.

2. Axis Movement

The high-speed CNC milling machines required for the process must be fitted with an axis movement system suitable for machining blisks, which should be at least 5 axes simultaneously, depending on the milling task involved and an efficiently high-speed control system.

3. 3D Surfaces

High Speed CNC milling machines working on 3D surfaces in any materials produce a finer surface finish and higher accuracy in less time that the traditional milling machine. Acceleration is the most critical factor that affects the high speed machining. Since one or more axis are always increasing or decreasing velocity in a 3-D cut, ultimate feed rate is directly related to acceleration

4. What Can A High Speed Control Possibly Do?

A CNC milling machine which possesses a higher structural stiffness has a greater potential acceleration rate. Box shaped high speed CNC milling machine, like Bridge and Gantry is the mostly widely used types of High speed CNC milling tools. The overhead type Gantry exudes the highest stiffness, acceleration and accuracy among other high speed CNC milling tools. Due to its scalability, this machine type is available in sizes to match the work piece, from small to large.

In usual terms, it simply gives you the ability to finish one task faster and move along to the next sooner, making work output higher. In drilling and tapping, this can result in faster hole-to-hole times, quicker spindle reversals for tapping, and substantial cycle-time reductions. The most dramatic benefits, though, come in 3D designs machining. Few, drilling and tapping jobs require a million lines of machine codes. In molds, dies, patterns, and prototypes, complex surfaces comprising a million or more line segments are not at all uncommon. Saving just a fraction of a second per move can result in substantial cycle-time improvements.

5. Downsides - When Is Fast Too Fast?

But despite all these benefits, in high milling, the tool path segments can be so short that a machining center moving at a high feed rate can’t accelerate or decelerate fast enough to make direction changes accurately. Corners may be rounded off and the work piece surface may be gouged. Look-ahead is one answer. Look-ahead capability can let the CNC read ahead a certain number of blocks in the program, to anticipate sudden direction changes and slow the feed rate accordingly.

6. Additional Benefits:

- Improved accuracy - Better fit - Superior finish - Better life - Produce more work in less time - Improving the accuracy and finish - Reducing polishing and fitting time - Tools simply last longer because their chip load is more consistent

About the Author

For more great milling machine related articles and resources check out http://www.millinginfo.com

Author Trevor Marshall

A CNC machine is used in woodworking shops and some other industrial settings. They are very expensive, so most individuals do not buy them, although used ones can be obtained more cheaply. They are important for speed and accuracy in large, repetitive tasks.

There are many uses in industry for CNC machines. Routers drill holes, for example. Many CNC machines can perform a number of tasks at once, improving efficiency in the manufacturing process.

The technology behind these machines is Computer Numerated Control. This technology was developed in the seventies and it allows for a machine to be programmed in advance so the operations are set up to work almost automatically. The initial setup is a little complicated, but once that is done the machine is easy to operate.

A CNC router would be programmed to drill a hole repeatedly at certain intervals. This is much more efficient than manual calculation and drilling and eliminates inconsistency due to human error or fatigue.

A CNC lathe would be used to cut pieces of wood of uniform size and shape. Lathes can have horsepower ranging from 15 to 40 HP, and how much power is needed depends upon the job being done. A good CNC lathe will allow you to work at various levels of automation, so that you can work all manual, or all automated, or any combination in between.

The best mill available is the Bridgeport mill. Mills are designed to be used in both large industries and small milling shops, and the Bridgeport mill is built to last in any situation. The price is prohibitive, however, for individual use.

A CNC mill is considered specialty equipment. The concept is to use computer programming and robotic operation for speed and accuracy. This kind of speed and accuracy would be impossible to achieve for an individual. The airline industry frequently uses the CNC technology of Bridgetown mills; specifications are entered, and the mill automatically determines which functions to perform and how.

Engravers can also be CNC machines. Engraving can be done on many materials, including wood or wood composite, metal, stone or glass. These machines can do very exact engraving on materials from the smallest to the largest, and have the same result over and over.

Since CNC machines are so expensive most individuals cannot afford them, there may be individuals who do a lot of repetitive machine work and would like to obtain one. An option in this case is a used CNC machine, which can be as low as half the price of a new one. It is important to make sure the used machine is in good condition, so you may be better off looking for a rebuilt machine. This is one that has had the major components replaced so it is almost a new machine. Frequently, rebuilt machines have a warranty of at least one year, so that you can be assured that it will be working, or you can get it repaired if it does not.

About the Author

Focusing on latest developments in woodworking tools, the writer publishes largely for http://www.insidewoodworking.com .
You can find his observations on cnc machines and tools at http://www.insidewoodworking.com .

Author Linden Walhard

Computer Numerical Control (CNC) machines perform functions of drilling, milling, turning, etc. CNC Mills are usually defined in terms of the number of axes they handle.

Axes are generally labeled as x and y for horizontal movement and z for vertical movement. The number of axes of a milling machine is significant. A standard manual industrial mill typically has four axes: * Table x. * Table y. * Table z. * Milling Head z. A five-axis CNC milling machine has an extra axis. This axis is the basis of a horizontal pivot for the milling head. This allows a greater flexibility for machining with the end mill at an angle with respect to the table. A six-axis CNC milling machine has another horizontal pivot for the milling head, perpendicular to the fifth axis.

Material is usually removed by both the end and the side of the cutting tool. In CNC milling the cutting tool usually rotates about an axis that is perpendicular to the table, which holds the material to be cut. Cutting tools of various profile shapes include: square, rounded, and angled. A wide variety of part shapes and geometries are possible by a CNC machine. Interestingly, CNC machines come in various models, which range from small desk-top lathes and milling machines to larger full-sized machining centers.

CNC machines used by www.eMachineShop.com are traditionally programmed using a set of commands known as G-codes. G-codes represent specific CNC functions in alpha-numeric format. CNC milling machines carry out the cutting process in which materials are removed from a block by a rotating tool. In CNC milling, the cutting tool is moved in all three dimensions to achieve the desired cut shape.

Online CNC machining ensures optimal work-related selection of manufacturing systems and the configuration to satisfy the range of parts to be processed.

A key advantage of CNC machining is the wide variety of work piece features that it can produce. Part features such as walls, pockets of different depths, tapped holes, bolt-hole circle patterns and others commonly found on prototypes can be precisely produced on a CNC machine. One other advantage of CNC machines is their ability to produce metal molds which can then be used for injection molding operations.

About the Author

George is a well-known author who writes on topics related to cnc machine shop, waterjet cutting, for the site www.emachineshop.com

Author George Ure

The process of manufacturing metal components is generally called metal fabrication. Metal fabrication processes may be classified as cold, warm, and hot working depending on the temperature at which the material is processed. At eMachineShop, many things are transformed by metal fabrication processes, such as bending, milling, cutting, punching, drilling, turning, grinding and threading. Metal parts made range from small parts the size of paper clips and even smaller using photochemical milling, to large industrial parts constructed using large CNC milling and turning machines.

eMachineShop uses a wide range of metal fabricating machinery and machining processes online to meet virtually all client metal fabrication needs. fabrication can be broadly divided into forming, removal and non-conventional, which is further sub divided into several categories.

* Forging : Forging involves forming work pieces by compressive force at high heat. Parts such as crankshafts, connecting rods, gears and bolt heads can be made by forging. * Rolling : Rolling is a process of reducing the thickness of a long work piece by compressive forces using a set of rolls. Plates used for Machine structures, vessels and sheets used for automobile and aircraft bodies, appliances and furniture are created by rolling. Rolled stock is often cut using water jet or laser cutters. * Extrusion : During extrusion round billets are forced through one or more dies by a compressive force that is applied to a ram. The extruded piece that emerges has the desired shape. In general, extrusion is used to produce cylindrical bars or hollow tubes, but shapes of irregular cross sections may be produced from the more readily extrudable metals, such as Aluminum. * Drawing : Drawing is the pulling of a metal piece through a die having a tapered bore by means of a tensile force that is applied on the exit side. Rod, wire and tubing products are commonly fabricated by drawing.

There are several methods of metal removing such as metal cutting, abrasive processes and non-conventional metal removing processes. Sawing, for instance, is a type of cutting in which the cutting tool is a blade that has a series of small teeth, with each tooth removing a small amount of material. Shearing on the other hand is a metal cutting process through which flat surfaces and various cross-sections with grooves and notches are produced.

Face milling and end milling are some of the types of cutting used. Grinding - on the other hand — is a chip removal process in which the cutting tool is an abrasive grain wheel. The different types of grinding processes are surface grinding, cylindrical grinding, internal grinding and centerless grinding. For extremely thin material, photochemical milling may be used. In this process, a caustic chemical etches away undesired material.

About the Author

George is a well-known author who writes on topics related to cnc machine shop, waterjet cutting, for the site www.emachineshop.com

Author George Ure

People new to product and part design need to know that CNC means ‘computer numerical control’. It generally means a computer controller for a cutting machine such as a lathe, milling machine, water jet (waterjet) cutter, or laser cutter, that reads G-code instructions and steers the machine cutting head - a powered mechanical device, typically used to fabricate metal components by the selective removal of metal. The most important benefit offered by a CNC machine is improved automation of part manufacturing. The operator intervention related to producing work pieces can be reduced or, on some machines, altogether eliminated. A second important benefit of CNC technology is consistent and accurate work pieces. This means that once a program has been verified, two, ten, or one thousand identical work pieces can be easily produced with great precision and consistency. Another reason why CNC machining shops have become popular is flexibility. Since these machines are run from computer programs, running a different work piece is almost as easy as loading a different program and different target material. Once a program has been verified and executed for one production run, it can be easily recalled the next time when the work piece is to be run . This leads to yet another important benefit, fast change-overs.

Since these machines are easy to setup and run, and since programs can be easily loaded, they allow short setup time. Various tools making use of CNC variants are: Drills EDM’s Lathes Milling machines Wood routers Sheet metal works Hot-wire foam cutters Plasma cuttings Water jet cutters Laser cutting Oxy-fuel At www.emachineshop.com , the online machine shop makes a wide variety of 2D and 3D shapes. CNC milling may be used to create engine components, custom and mold tooling, complex mechanisms, enclosures, etc. One advantage of CNC milling at eMachineShop is the cost effectiveness for short runs, with complex shapes cut from sheet, block or bar stock material. As you design parts, eMachineShop suggests you use the free eMachineShop software to try various combinations of machines and processes, along with alternate material choices to optimize your designs. Machining involves a material that is usually removed by both the ends and the side of the cutting tool. In CNC milling the cutting tool usually rotates about an axis that is perpendicular to the table that holds the material to be cut. Cutting tools of various profile shapes are available including square, rounded, and angled. A wide variety of part shapes and geometries are possible in this fashion. Keep in mind that CNC is not a total "computer solution." You should be aware that CNC milling requires not only software program tooling but in many cases work-holding jigs. This is why machine and material optimization - easily done within eMachineShop’s free CAD software - is so important to achieving the best possible price/performance result.

About the Author

George is a well-known author who writes on topics related to cnc machine shop, waterjet cutting, for the site www.emachineshop.com

Author George Ure