Printer Friendly

'Breaking news' was not a good thing for a broach maker: as coolants broke down, problems with its grinding operation rose.

General Broach Co., Morenci, MI, had coolant-splitting problems with the water-soluble coolants they used: because of the plant's hard water, the emulsion would fall apart.


As a leader in the manufacture of spiral gullet and button gullet broach bars, General Broach--GBC--had to take extra measures to ensure the concentration of coolant remained at the proper level to maintain a tight emulsion.

Beginning as a tooling operation in the 1940s, the company found business in the automotive industry. It was designated as the first in its industry to become a Ford Q1 supplier, and was one of the first to become ISO 9000 certified.

Five years ago, 90 percent of GBC's business was automotive-related. It supplied broaches to cut the internal, external, and blind splines for gears that go into automotive power-train parts. Because of the auto industry climate, GBC diversified. It changed its focus to aerospace customers and OEM manufacturers of off-road equipment, agricultural equipment, firearms, and hand tools. It manufactures broaches with diameters from 0.3" to 8.5" in diameter and up to 96" long.

General Broach grinds three different types of steel alloy material, M4, M2, and T-15. The lathe department trims stock to the required diameter, then the bars are hardened in a salt heat-treat operation that reaches 2,100[degrees]F.

The treating process can take up to three weeks. During treatment, the bars' temperature must be slowly increased so that both the inner and outer cores of the broach bar reach a hardness of 64 to 66 [R.sub.C]. After the bars are hardened, they are ground with vitrified CBN wheels taking off as much as 0.1" per pass.


Coolant Splitting Problems

GBC encountered splitting problems that translated into stress cracking and burn marks on the broach bars it was grinding. Because of these problems, it had to slow its grinding process--grinding at a slower speed and also reducing the amount of stock removed on each pass to insure the integrity of the part.

To worsen matters, the coolants it was using left slime on top of its sumps as the emulsion weakened and clogged its paper filters, causing rapid indexing of the filter paper. The company had to continually add coolant to keep the concentrate at the right level and the emulsion as tight as possible.

Because of the coolant splitting and the problems associated with it--rancidity, corrosion, and poor broach bar finishes--GBC evaluated NuSol from Chemtool Inc., Crystal Lake, IL.

GBC prefers mineral oil coolants because of the increase in lubricity for their part finishes and for increased depth of grind.

Once installed, GBC saw a 20 percent increase in production. The lubricant alleviated burning and stress cracks of the broach bars and increased feed rates, which translated into an additional 15 percent more production.

GBC was able to grind more stock with each pass. An added benefit was NuSol did not go rancid as their previous coolants had.

NuSol was also less expensive for GBC because operators did not have to continuously add coolant into the systems. The company reduced coolant consumption by 30 percent because it did not dump its sumps as often and it used less make-up coolant concentrate on a daily basis. Chemtool, Inc.

Visit for more information

Metalworking Lubricant for Food and Medical Applications

Accu-Lube LB-2000FM is a metalworking lubricant specifically designed to meet the needs of the food and medical industries. It is a natural, environmentally-safe metalworking oil for use in medical applications requiring machining, drilling, and tapping small diameters. It is applicable for sawing of solids up to 6" in diameter as well as tubing. It is consumed in the cutting process. It is non-toxic and biodegradable, eliminates flood coolant, and is safe for use on all metals. It is available in one and 55 gal containers. It meets guidelines specified by the FDA in 21 CFR 178.3570 for incidental food contact. ITW Rocol North America, Glenview, IL

Clear, Low Foaming Synthetic Fluid

Cimtech Synthetics provide clear, clean, low foaming, synthetic metalworking fluid for both heavy- and light-duty grinding and machining operations of ferrous and non-ferrous metals. The Cimtech fluids are formulated to reject tramp oil while providing a transparent substance. The Cimtech line can extend sump life, improve tool life up to 40 percent, and increase productivity up to 20 percent. Cimcool, Cincinnati


Hydraulic-compatible Neat-cutting and Grinding Fluids

Mobilmet 760 is an active, neat cutting, and grinding fluid series. Formulated with base oils and additives, the lubricants are for use in cutting stainless steel, titanium, nickel alloys and tool steel. The neat-cutting and grinding fluids exhibit anti-wear properties to minimize unscheduled maintenance and extend component service life. The lubricants are chlorine-free and come in three different viscosity grades, designed for applications such as broaching, gear manufacturing, and tapping. The fluids are compatible with the manufacturer's hydraulic, spindle, and slideway oils to help eliminate downtime associated with cross contamination. Exxon Mobil Corp., Irving, TX


Magnesium Machining Fluid

Blasocut BC37MG is designed for magnesium machining. It avoids instability, separation, and short fluid life associated with machining magnesium. It is a mineral oil-based, chlorine-free liquid tool. It is also suitable for other ferrous and non-ferrous materials such as brass and bronze, as it will not form insoluble lead soaps. Blaser Swisslube, Inc., Goshen, NY


Touch-up Blackener

Presto Black BST4 brush-on liquid is a fast-acting, cold blackener for iron and non-stainless steels. When applied to any clean ferrous metal surface, the BST4 solution blackens within 30 seconds and forms a durable, black finish that can be topcoated to form a black oxide. It is a fast-acting blackener of remachined areas or reworked metal parts and for quick repair of scratches or damaged areas on parts with a previously black-oxide finish. When the surface has turned sufficiently black, the liquid can be rinsed off with cold water. It will withstand the same degree of salt spray exposure as original black oxide. Birchwood Casey, Eden Prairie, MN

COPYRIGHT 2007 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2007 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Publication:Modern Applications News
Date:Nov 1, 2007
Previous Article:Building in critical cutting: an automotive supplier which had to meet both tight budget constraints and tolerances, turned to pivot-head sawing to...
Next Article:Three new CNC turning machines.

Related Articles
Taming the sludge monster; permanent filtration system manages coolant.
Keeping coolant clean. (Cutting Tool Talk).
Coolants/Lubricants/Filters Buyers Guide.
Coolant: why you need it.
Magnetic coolant cleaners are often the best solution.

Terms of use | Copyright © 2017 Farlex, Inc. | Feedback | For webmasters