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Study: High-Speed Machining Shops Should Take a Look at Brass

18. October 2018

U.S. machine shops with current or pending investments in machine tool upgrades can ramp up production speeds on brass parts with no loss of workpiece quality or tool life. These findings come from a recent study commissioned by the Copper Development Association Inc., which also found that current handbook values dramatically underestimate brass machining speeds and feeds.

The study, “High Speed Machining Advantages of Brass vs. Steel,” was carried out by Techsolve. 

Many manufacturers undershoot the machining capabilities of brass by up to 85 percent and have yet to benefit from the economic advantages that can be realized through high-speed machining, the study says. For example, single-point turning on modern CNC machine tools was shown to remove the same amount of brass up to 20 times faster than conventional machining rates applied on cam-operated screw machines. Even on a vertical machining center at speeds exceeding 16,500 rpm, brass produced little wear on carbide tools, yielding good surface finish and excellent chip control over the course of more than four hours of continuous turning. From an efficiency standpoint, production tests also showed that brass requires significantly less power per material removal rate than free-machining in both steel and stainless steel. A drilling test completed 1,000 holes in brass eight times faster than in stainless steel after optimizing machining parameters and cutting tools for both materials.

Brass allows manufacturers to take full advantage of today’s advanced machine tool capabilities, enabling shops to produce more parts in less time and with potentially lower costs per-part. Along with these production advantages, brass also offers 100 percent recyclability with full reusability of chips and scrap, which shops often sell back to raw material producers for 75 to 90 percent of the original brass value. Brass thus offers a favorable net material cost and a lighter environmental footprint compared to other machinable metals. For machine shops with high-speed equipment already on the floor, brass represents an opportunity to capture new profits they might otherwise miss with other materials, according to the study.

Find the study below. 

 

 

Five-Axis CNC Machining with an Angled Rotary Table

Posted by: Eli Plaskett 11. October 2018

One of the most reliable ways machine tool builders maintain workpiece stability is to build a sturdy, heavy frame and a solid bed to reduce the miniscule movements during machining that can cause tool deflection or chatter. However, five-axis machines have a somewhat less-stable worktable design. This is because of the rotation they must provide to position part at different angles.

According to Makino, different five-axis configurations have different benefits and challenges to consider, being that tilting the worktable along the A or B axes can compromise rigidity. For example, at certain positions, a swinging trunnion table can introduce leverage that amplifies micro-movements in the workpiece when the cutting tool makes contact, possibly resulting in deflection and chatter. While this loss of rigidity can be frustrating, the benefits of the complex contouring and single-setup machining are often more than enough to justify the investment. However, Makino recently developed the D200Z, which it says is designed to eliminate the need for a compromise. The company displayed the machine at Amerimold 2018, where it demonstrated how the CNC vertical machining center (VMC) achieves five-axis movement through a set of two integral rotating tables, one of which is tilted at a 44.5-degree angle.

According to the company, the permanent 44.5-degree tilt is a critical aspect of this rotary-table design. The tilted plate rotates about the B axis, while the rotary table attached to it rotates along the C axis, together enabling full five-axis machining and 3+2 machining. While a trunnion design involves making wide swings that drastically alter the center of gravity of the table, the D200Z can rotate fully around both axes within a comparatively small area. This improves stability by maintaining a center of gravity entirely within the physical diameter of the table’s bearings. The primary limitations are the size and mass of the workpiece. If it is larger than 165 pounds (75 kg), the benefits of the tilted rotary table begin to decrease compared to larger trunnions or articulated spindles.

The Makino D200Z achieves full five-axis machining through a novel system of joined rotating tables.
 

Designed for Moldmaking

Machine rigidity is particularly important in moldmaking applications. High-speed machining to precise tolerances requires anticipating chatter or deflection to avoid scrapping an expensive mold core or cavity. “The table design ensures that the center of gravity is always within the capture range of the bearings,” says Bill Howard, Makino product line manager. “Therefore, regardless of the desired angle or rotary position, the design provides and maintains stiffness and rigidity, as well as ensures excellent kinematics and motion control.” By balancing the need for maintaining rigidity, the D200Z is designed to reduce chatter and deflection in mold machining, as well as other applications that require high precision or have complex part geometries.

Additionally, the tilted rotary table is said to ensure sufficient clearance for the spindle to access critical part features. With a free-standing rotary surface that only attaches to the rest of the machine from the bottom-center of the table, the spindle is designed to easily access five sides of a part, and the cutting tool can reach deep into pockets for molds. The table’s geometric simplicity also simplifies chip evacuation, as moving to a vertical position enables chips to fall into a conveyor, available as a standard feature.

A Compact Solution

The compact work area also reduces the machine’s footprint, leaving room for attached tool changers or automation cells. Further, the small work area and tilted table reduce the distance operators have to reach in order to load and unload parts, reducing the physical toll and increasing the ergonomics for the user.

Additionally, the compact workspace increases manufacturing speed. Because the machine tool is capable of achieving full five-axis movement and positioning in a small work area, it requires relatively small movements to reach desired orientations. The small movements translate into fast positioning for the workpiece.

Proper Programming

Howard asserts that anyone used to working with five-axis CNC machines should have no problem programming this one. “I would think that anyone familiar with any CAD/CAM system that generates and evaluates tool paths for five-axis machines would have no difficulty programming the D200Z,” he says. 

Find machine specifications for Makino’s D200Z here on Techspex

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This blog post was adapted from a piece that originally appeared on Modern Machine Shop.

 

10 Videos from IMTS 2018

5. October 2018

IMTS 2018 is over, but whether you attended the show or weren’t able to make it this year, it’s worth a recap. Here are some videos taken by editors of Modern Machine ShopMoldMaking TechnologyAdditive Manufacturing and Production Machining magazines as wel as by attendees and exhibitors during the show.

 

 

Change vs. Progress: Reflections from a 25-Time IMTS Attendee

Posted by: Jedd Cole 20. September 2018
IMTS Show floor

Image: AMT – The Association For Manufacturing Technology.

 

During IMTS last week, Hexagon Manufacturing Intelligence recognized Burt Mason, a portable arm measurement specialist, with a tribute for having attended a whopping 25 editions of IMTS! On the occasion, he reflected on the almost 50 years this represents: 

After recounting the growth of CNC and CAD/CAM technology into the mainstream, Mason observed that these changes, being incremental by nature, were very gradual—“so gradual that if you asked people what they saw at IMTS that was unique or interesting most people would say, ‘There is nothing really new at the show this year,’ yet the changes were there show after show.”

It’s a good reminder that change most often comes not in sudden grand revelations but rather the step-by-step meandering of day-to-day problem solving and the effects of policies, both spoken and unspoken.

If I can add anything to Mason’s words, I’d say that change isn’t identical with progress. For example, the movement toward the looming labor dilemma that preoccupies many a shop both large and small has been just as incremental (and multifaceted) as the developments in CNC and CAD/CAM technology. To agree with Mason’s conclusion, it would do us well to pay attention to the incremental shifts that go on around us, whether or not they are intentional. Maybe that way we can contribute positively to the changes that we’ll look back on in the future.

 

Technology Featured at IMTS 2018

6. September 2018
IMTS 2018 technology collage

In the lead up to the International Manufacturing Technology Show (IMTS), taking place September 10-15, OEMs send out hundreds of press releases detailing new machine and technology releases to be featured at the show. Modern Machine Shop, with its sister publications, Additive ManufacturingProduction Machining and MoldMaking Technology, round up many of these and publish them in advance of the show. Find all of the ones these metalworking magazines accepted online: mmsonline.com/zones/browse/imts/3.

Here is a sampling of such releases from Techspex’s supporters: 

 
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