Not Settling for Less

A-POT point tap eliminates burrs and doubles tool life

Fernando Arzaluz  |  OSG Royco

MACIMEX, founded in 1979, is a subsidiary of Grupo Quimmco and is one of the world’s largest independent crankshafts manufacturers. MACIMEX is dedicated to the machining of cast iron crankshafts from two to eight cylinders for engines and compressors with weights ranging from 1.9 kg (4 lb.) to 42 kg (92 lb.). These crankshafts are used in a wide range of industries, such as automotive, industrial, agriculture, recreation and marine. According to MACIMEX, the company manufactures over 1 million crankshafts per year and exports 50 percent of its production to customers worldwide.

MACIMEX’s Tenango del Valle production facility produces over 1,800 crankshafts per day. As a leader in the field, MACIMEX is constantly looking to improve production in terms of efficiency and quality. Hoping to improve the tapping performance of the crankshaft’s flange, which consists of a total of eight holes, the company contacted OSG. The hole diameter is 9.5 mm with a hole depth of 500 mm (through-hole). The material of the crankshaft is forged steel alloy SAE 1438MV with a hardness of 38 to 40 HRC. For this application, MACIMEX uses a horizontal machining center with synchronized feed and rotation.

MACIMEX was facing poor performance by using a spiral point TiN coated M11 x 1.5 tap from a different tooling manufacturer, which averaged a tool life of 1,600 holes. MACIMEX was running the competitor tool at a cutting speed of 17 m/min. Internal-fed water-soluble coolant was also applied. The tool life judgment was GP out but MACIMEX also experienced problems with burrs. The cost per unit with the competitor tool was $0.0475 (USD) with five tool changes per day.

Upon a detail evaluation of the application, OSG proposed the A-POT tap M11 x 1.5 (special) from the A-Tap series. OSG’s A-Tap is an all-purpose tap series designed to simplify tool management and to excel in a wide variety of materials and applications. The series offers spiral flute (A-SFT) and spiral point (A-POT) in a wide range of sizes. To accommodate a variety of cutting conditions, powdered metal HSS and OSG’s patented V coating have been employed in this series to achieve excellent wear resistance. In addition, to enable high speed machining, the A-Tap series incorporates a unique cutting edge design that emphasizes sharpness. Not only does the A-Tap series perform well in general steel, it also excels in difficult to machine materials such as stainless steel and mild steel.

The sharp cutting edge, variable flute helix and high wear resistance helped to eliminate the burr problems, and the tool life was increased to 4,000 holes, more than doubled the durability.

OSG’s A-POT point tap was used to improve the cost efficiency in the production of crankshafts at MACIMEX.

OSG’s A-POT point tap was able to eliminate burr problems to improve hole quality.

The cost per unit went from $0.0475 (USD) to $0.0166 (USD), which is a 65 percent savings, and only one tool change was required per day. As demonstrated by this case study, not settling for less is the formula to successful mass production.