Hannibal Carbide has assembled a very nice overview of some common problems associated with carbide reamers and how to avoid them.
Make sure you are using the correct flute style and tool type.
HANNIBAL recommends 2-3% of the reamer diameter as a starting point for stock removal. 2% for steels and tough alloys, 3% for non-ferrous materials and cast irons. Solid carbide & carbide tipped reamers must have adequate stock to remove or they will rub in the hole and generate excessive heat, which leads to premature tool wear.
Improper Speeds & Feeds
The right combination of speeds and feeds is critical to tool life and consistent size and finish. Getting the correct starting points is a key element. Reaming is a finishing operation and proper speeds and feeds must be run to achieve size, straightness and finish.
If the fixturing cannot hold the piece securely and in line with the spindle, then producing a good finish will be very difficult. A reamed hole is only going to be as good as the machine and fixturing used to machine and hold the part.
Excessing Runout (spindle or tool holder)
Runout leads to poor finishes, oversized, tapered, and bellmouth holes, as well as poor tool life. Floating holders or bushings can sometimes be used to compensate for runout, but the best solution is to fix the problem.
Make sure the coolant you are using is recommended for reaming your particular materials. Many coolants will prove effective for reaming if the concentration level is maintained with specifications. Take the time to check the levels on a regular basis.
Improper Sharpening or Geometry
If a new tool works fine, but fails to perform after resharpening, the problem is obvious. However, depending on the hardness and condition of the material you are reaming, the tool geometry may need to be altered to get optimum performance and tool life. Geometries most often changed are the circular margins, radial rake, and the primary chamfer clearance.
Material Changes (hardness and/or condition)
Castings lead the way in inconsistency. Hard spots, free carbides, and scale can all lead to inconsistent results when reaming. A heat treatment that varies just a few points from part to part can cause problems.
McLean, Va. (April 8, 2019) – Manufacturing technology orders totaled $337.2 million in February 2019 accounting for a 15 percent decline from January and a seven percent decline from the previous February, according to the latest USMTO report from AMT. The year-to-date total was $735.2 million, less than one percent off the year-to-date total at this point last year.
“It’s important to look at the February numbers in context. It’s true that order levels declined, but from the second strongest January in the history of the USMTO program. They’re still at good levels compared to this time a year ago,” said Douglas K. Woods, President, AMT. “Other indicators signal continued manufacturing strength. AMT members are generally positive heading into the second quarter; the U.S.-China tariff negotiations look to be moving toward a successful conclusion; and the March ISM Manufacturing PMI showed expansion which beat analysts’ expectations and rallied the stock market. However, uncertainty lingers on issues such as tax, trade and the budget, and continued inaction in Washington could stall already sluggish growth.”
While companies in many industries reduced their orders in February, the nearly 50 percent decline in orders placed by the Aerospace as well as Engine and Turbine industries led the downturn between January and February. The Automotive sector recorded a modest double-digit uptick. Bucking the general trend, February 2019 had a notable expansion in orders from Commercial and Service Industry Machinery Manufacturing such as Water Treatment and Commercial Cleaning Equipment. The big gain was the result of large orders in the Great Lakes area and the West.
Four of the six USMTO regions had fewer orders in February than January, with the largest decline coming from the Southeast. In the West, metal cutting orders rose slightly. However, declines in Forming and Fabricating lead to roughly stagnant orders compared to the previous month. The South Central region outperformed all other regions, with orders expanding by over a third from January 2019 led by growth in Oil & Gas, Contract Machining, and Food Processing Equipment sectors.
Capacity utilization had a second month of declines in February, settling at 77 percent, off the post-recession high of 77.8 percent in December 2018. Despite an increase in orders from the Automotive Sector, Light Vehicle Sales rebounded to 17.477 million annualized units in March. March Manufacturing ISM® Report On Business® registered a Purchasing Manager’s Index of 55.3 percent, an expansion of 1.1 percentage points over February, signaling underlying strength in the manufacturing sector.
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