As one of the first blogs to report on energy efficiency in CNC machining, We felt it important to post on Siemens new product the Sinumerik Ctrl-E.  This post contains specs on the product and how it can help save in electricity cost as well as aid your business in garnering a “green” reputation. According to a recent EU Commission report, industrial production accounted for 40 percent of total power consumption in the EU-27 in 2007, of which 70 percent was used by electrical drive systems. Depending on the company involved, machine tools can account for up to 68 percent of the total energy requirement. This fact makes energy efficiency in manufacturing a decisive factor in reducing plant costs and improving overall competitiveness. Siemens kept this in mind when it carried out an energy analysis of individual machine tool components with the goal of achieving significant cuts in energy consumption through Sinumerik Ctrl-Energy.

With Sinumerik Ctrl-Energy, Siemens has opened up a broad range of solutions for the energy-efficient operation of machine tools, encompassing its Sinamics drive systems and motors, CNC and drive function and PC software solutions. Sinumerik Ctrl-Energy offers energy-efficient solutions covering every aspect of the machine’s lifecycle, starting from machine design and engineering through machine operation and partial or complete retrofit. This makes Sinumerik Ctrl-Energy a broad-based platform for efficient machine management, which will benefit both the machine tool OEM and end-user.
By holding ‘Ctrl E’  on the operator panel, Sinumerik CNCs can provide a fast evaluation of the machine tool’s energy consumption and also manage energy consumption during machine downtime. Using the ‘Ctrl-E Analysis’ function, Sinumerik controls determine both the energy consumption of a drive system and the entire machine. They enable the user to analyze the amount of energy that goes into machining every individual workpiece as the basis for machining strategy improvements. The ‘Ctrl-E Profiles’ function also provides a configuration platform for the management of the machine’s energy saving modes, helping to selectively shut down specific power loads during downtimes.

FREQUENCY CONVERTERS AND ENERGY-SAVING MOTORS — THE INTEGRATED DRIVE TRAIN AS A CORE ELEMENT OF OVERALL ENERGY EFFICIENCY
The Siemens Sinamics S120 drive system permits dynamic energy management in the DC link and makes use of a highly efficient power recovery system, which initially stores generated braking energy in a DC link and optionally feeds it back into the grid rather than allowing the brake resistance to turn it into heat. Sinamics drives and Siemens motors have been designed with a clear focus on energy efficiency aspects. In this manner, integrated drive modules from Siemens reach a high efficiency rating of 97–99 percent.

With an efficiency of up to 94 percent in synchronous motors and up to 91 percent in asynchronous motors, the Siemens motor range also provides a basis for energy-efficient machine designs. In a typical machine tool, auxiliary assemblies such as hydraulic supply systems or cooling and lubrication units account for over half the total energy consumption. Energy-saving 1LE standard asynchronous motors have an efficiency rating of up to 97 percent and offer significant potential for auxiliary assembly improvement. The use of Sinamics G120 frequency converters helps adjust the speed and also the energy consumption of auxiliary systems to the level required at each stage of
the process.

POTENTIAL SAVINGS: CURRENT FLOW REDUCTION AND POWER FACTOR COMPENSATION
Sinamics S120 drive systems permit automatic current flow reduction in asynchronous spindles operating under part-load, avoiding unnecessary heat loss. The reactive power of a machine can be fully compensated using the smart infeed and feedback modules of Sinamics S120 drives, rendering costly and loss-prone reactive power compensation units on the end user’s premises superfluous.

CONTROL CABINETS ALSO HELP EFFICIENCY
Control cabinets, along with the required dissipation of heat, have a significant impact on the energy balance of a machine. Siemens can supply machine tool builders with a complete control cabinet that is designed with optimum energy management in mind. Various cooling options exist, including cold plate and direct fluid cooling, which reduce the need for air-conditioning in the control cabinet and make waste heat produced by the drive systems available elsewhere in the form of process heat.

SIZER — THE CONFIGURATION TOOL FOR ENERGY-EFFICIENT DRIVES
Sizer is the Siemens software tool used to configure energy-efficient drives. It calculates energy consumption and losses incurred with the anticipated load cycles (ramp-up, idle running, running under load, braking, cycle times etc.), as well as the influence of regenerative feedback. This allows the energy efficiency of alternative motor/converter combinations to be evaluated. Using this information, configuration of the feed and main spindle axes can be optimized in line with the process and the anticipated cyclical work flows. Sizer also helps users to avoid over-dimensioning, also in terms of infeed, and to minimize energy consumption.

On the surface, aerospace machining is pretty straightforward: precision operations done a step at a time. Although exacting, it’s frequently left-brain work that’s comfortably predictable. It’s mostly pocket milling, process monitoring and prescribed recordkeeping. Or is it?

Arguably, no other sphere of manufacturing attracts so many imaginative thinkers – big-picture types who ignore trivia, but are passionate about essential details. They’re innovators like Edvaldo Antonio da Rosa, the founder of a cutting-edge Brazilian aerospace shop with a name that evokes Japan – Toyo Matic.

Located in the southern city of Bragança Paulista, about 85 km north of São Paulo, Toyo Matic serves prominent clients in the Americas, Europe and Asia. According to its customers, Toyo Matic helps put Brazil on the map as a center for modern precision machining. “That’s been our ambition since day one,” says da Rosa, with a smile. “We love to hear people say: ‘You can’t do that in Brazil!’”

The 20-year-old company earned its reputation by routinely doing the nearly impossible. Although it boasts a crew of 75 skilled machinists, operators, engineers and office staff, Toyo Matic’s success reflects the drive and technical talent of its energetic founder. With typical Brazilian humor, associates declare that if da Rosa stepped into a revolving door one space behind them, no one would be surprised to see him exit first!

Not So Simple

As prime aerospace manufactures strive to build with weight-saving monolithic components, the “nearly impossible” has become a common request. When Brazilian aircraft manufacturer Embraer recently combined several hydraulic control components for their popular ERJ-170/190 aircraft into a simpler monolithic unit, it proved to be anything but simple to make.

After eight companies in three countries failed to find a cost-effective way to manufacture the part, Embraer probably started having second thoughts. Fortunately, the design packet found its way back to Brazil – and Toyo Matic. “It’s now the most difficult part we make,” confides da Rosa. “It took many months of testing to develop the procedures.” The heavily milled 7075 aluminum block manifold has deep, intersecting blind holes, some as small as 2 mm diameter. Numerous other bores, recesses and curved surfaces often require 6-micron tolerances, and it requires 160 individual CMM checks to generate the final 61-page inspection report that accompanies each unit!

Toyo Matic solved many of the problems that baffled others by optimizing their tooling to reduce the major causes of inaccuracy: vibration, thermal growth and chip-induced tool runout. “We’ve distilled the manufacturing process down to only six operations,” da Rosa explains, “but we use 112 different tools!”

Finding the “technically sweet” tooling solution was a creative effort well suited to da Rosa’s talents. Before returning home in the 1980s to start Toyo Matic in Brazil, he worked in Toyokawa City, Japan, for the large international tool manufacturer, OSG Corporation. “I suppose,” he notes, “that’s one of our secrets.”

Secrets Too Numerous

Instead of searching tool catalogs for the perfect solution, da Rosa takes a more direct approach. “Whenever I have the time, I always build my own tools,” he explains. “The advantages are just too numerous to ignore.” By making his own, da Rosa can optimize each milling tool’s length-of-cut ratio for each operation – this usually means producing the shortest possible tool to do the job. Standard-reach tools are usable for a wide range of operations, but their longer shafts make them prone to axial runout, deflection and vibration. This is especially true when subjected to the heavy side loads of aggressive pocket milling – the most common scenario in an aerospace shop. The traditional way around these problems is to slow the feedrate. But that lengthens cycle time and can cause new problems, especially in hard materials like titanium, where a reduced feedrate can cause galling and work hardening. Also, with the reduced chip load, heat can quickly build up at the cutting edges, significantly shortening tool life. “Changing to the proper length tool is the better solution,” offers da Rosa, “even though the better solution isn’t always the obvious one.”

What about deep-reach situations where a longer tool is required? Again, da Rosa’s optimized approach pays off. He makes exact-length tools with an integral 40- or 50-taper base that allows direct mounting in the machine spindle. By eliminating the toolholder altogether, he bypasses a major source of runout error. It is this kind of ingenuity motivation toward precision that gives a shop the innovate edge in the CNC business.

A milling machines is a machine tool (powered mechanical device, typically used to fabricate metal components) used to machine solid material. Milling machines are often classified into two basic forms: Horizontal and Vertical, which refers to the orientation of the main spindle. Both the types range in size from small, bench-mounted devices to room-sized machines. Milling machines can move the work piece radially against the rotating milling cutter, which cuts on its sides as well as its tip. Milling machines may be manually operated, mechanically automated, or digitally automated via computer numerical control (CNC).

A  vertical milling machine is a machine in which the spindle axis is vertically oriented. Milling cutters are held in the spindle and rotate on its axis. The spindle can generally be extended allowing plunge cuts and drilling. A horizontal milling machine is a machine where the cutters are mounted on a horizontal arbor across the table. A majority of horizontal milling machine also features a +15/-15 degree rotary table that allows milling at shallow angles.

A CNC milling machine is an automated milling tool that can cut 3D shapes out of a block of material. Most CNC milling machines are computer controlled vertical mills with the ability to move the spindle vertically along the Z-axis. The extra degree of freedom permits their use in die sinking, engraving application, and 2.5 D surface such as relief sculptures. When combined with the use of conical tools or a ball nose cutter, it also significantly improves milling precision without impacting speed, providing a cost-efficient alternative to most flat-surface hand-engraving work.

CNC machines can exist in virtually any of the forms of manual machinery, like horizontal milling machines. The most advanced CNC milling machines, the multi-axis machine, add two more axes in addition to the three normal axes (XYZ). Horizontal milling machines also have a C or Q axis, allowing the horizontally mounted work piece to be rotated, essentially allowing asymmetric and eccentric turning. The fifth axis (B axis) controls the tilt of the tool itself. When all of these axes are used in conjunction with each other, extremely complicated geometries, even organic geometries such as a human head can be made with relative ease with these machines. But the skill to program such geometries is beyond that of most operators. Therefore, 5 axis milling machines are practically always programmed with CAM.

What is CNC Router

A CNC router is a computer controlled tool for cutting various type of product such as wood, plastic, aluminum, steel and other kinds of metal. CNC routers comes in many configurations including the small home style known as “Desktop CNC Router” to the larger ones known as “Gantry CNC Routers” which are used on boat making facilities. Though there are many configurations, still most of the CNC routers have a few specific parts in common, likes CNC controller, one or more spindle motors, AC inverters, and a table. Generally CNC routers are available is 3 axis and 5 axis formats.

CNC router works like a printer. Work is composed on a computer and then the design or drawing is sent to the CNC router for the hard copy. As CNC routers are run and controlled by a computer, coordinates are uploaded into the machine controller from a separate program. There are basically two programs used, one to make designs and another to upload designs to the machine and run it. CNC routers can be run and controlled directly by manual programming, but the full potential of the machine can only be achieved if they are controlled from the file created by the CNC software (such as “CAD/CAM”).

Advantages of CNC routers:

1) Can be very useful when carrying out identical, repetitive jobs.

2) Produces consistent and high quality work and improves factory productivity.

3) Can reduce waste, frequency of errors and the time the finished product takes to get to market. For Example: CNC routers can perform the tasks of many carpentry shop machines such as the Panel saw, the spindle molder, the tunnel boring machine, and can also cut mortises and tennons.

4) Gives more flexibility to the manufacturing process.

5) Can be used in production of many different items, such as door carvings, interior and exterior decorations, wood panels, sign boards, wooden frames, moldings, musical instruments, furniture manufacturing and many more.

6) Can also make thermo-forming of plastics by simply automating the trimming process.

G-code is the common name for the most widely used numerical control program language. G-codes are also called as preparatory codes, and are any word in a CNC program that begins with the letter “G”. G-code’s programming environments have evolved in parallel with those of general programming from the earliest environments like writing a program with a pencil or typing it into a tape puncher to the latest environment that stack CAD, CAM and richly featured G-code editors.

Generally it is a code telling the machine tool what type of action to perform, such as:

• Rapid Move

• Controlled feed move in a straight line or arc

• Series of controlled feed moves that would result in a hole being bored, a work piece cut(routed) to a specific dimension, or decorative profile shape added to the edge of a work piece

• Set tool information such as offset

G-code began as a limited type of language that lacked constructs such as loops, conditional operators, and programmer-declared variables with natural-word-including names (or the expressions in which to use them). It was thus unable to encode logic; it was essentially just a way to “connect the dots” where many of the dots’ locations were figured out longhand by the programmer. The latest implementations of G-code include such constructs, creating a language somewhat closer to a high-level programming language. The more a programmer can tell the machine what end result is desired, and leave the intermediate calculations to the machine, the more s/he uses the machine’s computational power to full advantage.