Improving Process Efficiencies in Coremaking

April 11, 2005
It gives foundries a capability that no other metalworking process offers: the ability to form external and internal contours, shapes, cavities, and passageways in one operation.

Foundries have always been interested in improving productivity and profitability. But, over the past few years competitive pressure and general industrial conditions have reinforced metalcasters’ resolve to refine current processes and to develop new technologies that improve productivity and reduce costs.

One area where foundries look to improve process efficiencies and cost savings is the coremaking process.

Coremaking is central to metalcasting. It gives the industry the edge that no other metalworking industry has — the ability to form external and internal contours, shapes, cavities, and passageways in one operation. Thus, the importance of producing high-quality cores efficiently and inexpensively cannot be underestimated.

Historically, cold-box core production equipment was selected, piece by piece, by a foundry’s engineering department with input from core room supervisors and foundry managers. Workable systems were assembled with compatible components, and cores with good quality were successfully produced.

Design demands
Now, the pressure is increasing for engineering staffs to reach performance and productivity targets. Many of these engineers are shouldering heavier workloads, thanks to factors like the poor economic conditions at many companies, and the competition to recruit and maintain the best talent on staff. The result is that the responsibility for putting together systems with well-matched components has moved to equipment manufacturers and (sometimes) engineering companies, where qualified engineers and resources are available.

The idea of a properly integrated cold-box core production system gives the foundry end-user the assurance of knowing there is a single-source system responsibility — a powerful tool for the buyer if a problem emerges anywhere in the system.

A properly integrated core-production system helps produce cores with higher quality than a less perfectly matched system. Why? Sand, resin, catalyst and additives can be metered into the system precisely and with proper control of important physical conditions. Also, the value of specifying, purchasing, and installing a complete core production center is real. It is worth the investment cost, whether the requirement is a single core machine or multiple units sharing some of the support components.

Therefore, finding the right coremaking supplier is of critical importance to many foundries. Here are some of the stories of a few metalcasters in search of the perfect core.

North and south
How did a foundry in Alberta and a supplier in Alabama ever find each other? “We are off the beaten path,” acknowledges Bart Davies, vice president, production and sales at Lethbridge Iron Works in Lethbridge, AB. “We don’t get a lot of visits from equipment suppliers. But, Laempe has been a pleasure to deal with. They are responsive and stand behind what they promise.”

Laempe is (A HREF="">Laempe + Reich, a Trussville, AL, company begun by the Reich family three generations ago. Still selling and supporting core-production equipment, today’s Laempe + Reich has installed more than 250 Core Centers in North America alone.

“We did some shell core (production), but we never did enough to really master it,” explains Davies. “So, we looked at other ways to save coremaking costs. We did our homework. We visited various foundries to find out what they were doing and discovered we could save money by increasing our isocure (cold-box) coremaking capabilities.” Their research led Lethbridge to purchase a Laempe LL-110 in 1998, and an LB-25 in 2003. Davies estimates that 60-65% of their coremaking is done with the Lamepe machines now. “We still do some shell coremaking,” Davies elaborates. “We feel that in some instances shell coremaking can provide better quality, dimensionally and cosmetically, but in terms of process efficiency, the Laempe + Reich machines can’t be beat.”

Friends and neighbors
When Neptune Technology Group, a low-lead brass castings manufacturer in , Montgomery, AL, was ready to replace an air-set core machine, they looked just up the road to Laempe + Reich. “This was our first time dealing with them,” explains Deric Murphy, foundry engineer. “Their reputation for quality preceded them and we visited other foundries with Laempe installations. Basically, though, it came down to the fact that they were able to accommodate the large core size we needed to run.”

So, in the first quarter of 2003 Neptune purchased its LB-25. “They converted all our tooling,” enthuses Murphy. “That is pretty unusual. Typically you have to totally re-tool for a new machine, which can really run up the costs. Plus, they helped us to develop the best way to convert the tooling.”

In the past Neptune performed some shell coremaking, but since installing the LB-25 that process has been mostly discontinued. “We do some, but very little. With the LB-25, cold box really has become our bread and butter.”

As far as reliability and customer support, Murphy is pleased to report that they have not had a problem that would shut down the process. “Any problems we have had, they’ve come right down to help,” he states.

RH Sheppard, a Hanover, PA, manufacturer of finely engineered products for the truck, bus, rail, construction, military, and recreational vehicle industries also runs two LB-25s, as well as an LL-110. “I’ve known the Reichs since 1989 and used Laempe + Reich machines in the foundry where I worked earlier, so I knew they were good,” explains Frank Hueske, v.p. and general manager at RH Sheppard. “Since installing these three machines about four and a half years ago, we’ve seen fantastic improvements in our process efficiency. We converted a lot of our shell to cold box, which was more efficient and really lowered our costs. We were able to reduce staffing from 70 people down to 30.”

According to Hueske, another advantage, is that Laempe has parts available all the time if one is needed. “They provide you with a manufacturer list so you don’t have buy from them. You can buy directly from the OEM,” adds Hueske, with emphasis. “That is rare.”

Coremaking Equipment Buyers' Guide

Foundries’ operating experience and equipment builders’ design expertise result in frequent updates and advances in coremaking processes. The result is a world of options available to buyers of coremaking equipment and systems.

Loramendi supplies turnkey coremaking systems for automatic production using the patented Key Core or gluing core interlocking systems, or individual machines for single core production. The SLC coremaking machine for horizontally and vertically parted tooling is an improvement to an earlier Loramendi design, and it’s capable of very short cycle times and optimized corebox and production changes. It produces quality cores because its advanced blow system minimizes the sand lost during blow plate change, and increases tooling life. User friendly, this coremaker is also rugged and flexible, with continuous clamping and no corebox movement throughout the blow and cure cycle. No special foundations, pits, or operator platforms are required. Cores are unloaded at a height convenient for the operator. PLC controlled, with integrated blow plate and blow head cleaning systems and built-in exhaust connections.

Loramendi also offers its “classic” SHA coremaking machine for horizontally parted tooling in several design variations.

The SVA model has been optimized for vertically parted tooling, with bottom mandrel and optional top mandrel. Core boxes are constantly closed under high pressure with no movement during the cycle, ensuring dimensionally accurate cores with no fins. The integrated blow plate and blow head cleaning system is fast and easy to use, making sure that no sand is spilled inside the machine.

Loramendi’s corebox fast-changing shuttle is a dual-station carriage installed at the back of the machine to perform the change. The used core box comes out to the first station with the blow and gassing plates on top, while the new tooling is waiting on the second station, to enter the machine. Also available, a purpose-built manipulator installed at the back of the machine to remove the used corebox and pilled plates and deliver a new set of tooling to the machine. The SLC-K is a variation of the SLC coremaker that changes production in less than a minute thanks to the corebox turning table and side-blow plate change.

The Simpson Group’s catalog of foundry technologies includes core machines, core-sand preparation plants, gas generators, odor scrubbers, and shell sand preparation plants.

Good coremaking begins with high-quality core-sand preparation, according to Simpson. For the demands of advanced coremaking operations, Simpson offers the patented, CE-certified CSM Series Core Sand Mixer, which it bills as “the most accurate, versatile, and productive core sand preparation system available in the world today.” Among its attributes:

Accurate (±1.0%) binder addition, for cost-effectiveness; an integrated, multi-batch sand hopper, for accurate sand proportioning; programmable set points for the sand charge and the binder level; and a 100% cast-urethane mixing chamber to minimize material build-up. And, the mixing bowl is mounted to a threaded spindle so it can be quickly and easily lowered away from the mixer frame, for inspection or maintenance.

The CSM is outfitted with ultrasonic sensors, variable-frequency drive, load-cell weigh systems, and custom software.

The CSM Series is offered in 35-Kg and 125-Kg batch capacities, and capable of producing approximately 3.1 and 8.4 tons/hour (respectively). Either model can be operated as a single core machine or, with sand-handling equipment, to service several core machines in a cell.

Simpson also offers the Beardsley & Piper line of coremaking equipment. The B&P Flexiblo (for manual operation) and Flexiblomatic (for automatic operation) are designed for horizontally parted tooling, with operating capacities ranging from 5 to 400 lb of blown sand. They can be equipped for any modern coremaking process. B&P compliments the Flexiblow line with the Flexigas gassing units, which offer 0- to 30-second adjustable gassing time, full 4-in. draw automatic gassing cycle, and a pneumatic circuit that’s called “maintenance free.”

B&P’s SF Corematic is a time-tested, automatic hollow shell coremaking machine that is compact and sturdy, and offered as a complete system with a sand hopper and heating unit.

The Cormatic offers savings in installation cost, operating cost, and maintenance cost. It is rugged, heats core boxes more efficiently, and its compact design requires minimal floor space. Operation is programmable, with up to 500 sets of corebox parameters possible for simple changes.

The B&P Roto Mold Cormatic is designed with three or four stations, to operate with one or more coreboxes. Available for horizontal or vertical tooling, it can run both kinds of core boxes simultaneously: The first station blows the core, the second performs gas and purge, the third removes the core. The Roto Mold Corematic can be packaged with a sand mixer, gas generator, and scrubber for a complete system.

Dependable Foundry Equipment Co. and Redford-Carver Foundry Products Co. boast they offer the “widest range of equipment available for foundries using chemically bonded sand processes.” For cold process operations, Redford Core Machines are rugged and dependable for all popular cold box (gas-cured) processes. Twelve models are offered to produce cores as large as 150 lb (68 kg). Redford HCB and CB machines are made for dedicated use either with horizontally or vertically parted coreboxes, and feature fast, automatic operation — including sand blowing, gassing and purging cycles, and mechanized core removal on selected models. All Redford machines use a high-capacity blow system and a dual-head mechanism, including a sand magazine head and a combination gas/purge head with a built-in core ejector feature on HCB models.

For hot processes Redford manufactures 17 models, the largest capable of producing solid shell cores up to 200 lb. They operate with all popular hot box, warm box, and shell processes, using natural gas or bottled gas for heating. Automatic dual-temperature control is included.

Redford hot process machines are for dedicated use with horizontally or vertically parted coreboxes, and feature automatic operation of the production cycle, including blowing, heating/curing, ejection, and mechanized core removal on selected models. Hot process cores provide fast cycle times, high core density, good dimensional accuracy, and high tensile strength. Shell cores are produced using separate blow and drain systems (including automatic sand return) for efficient production.

Hollow cores may be effectively produced with DF Shell Core Machines, using the shell method with resin-coated sand. Shell core production is relatively fast and efficient. The machines have hydraulically powered corebox “rocking” to ensure that sand is invested into all cavities, and that all loose sand is drained away before cores are cured and removed.

DF Shell Molding Machines produce molds by curing a hardened layer of resin-coated sand directly on a heated pattern, for castings requiring exceptional surface finish. They are offered as complete systems: heating control for pattern plates and curing the reverse sides of molds; rollover for investing the pattern with coated sand; ejectors for stripping the mold away from the pattern and automatic retractor forks (on standard model) for removing the mold from the machine.

Redford’s CoreCommand cold-box core production systems combine high performance with the flexibility to produce quality cores in production and utility applications.

Gaylord Foundry Equipment offers a line of core-room equipment that includes gas generators for amine, sulfur dioxide, and methyl formate; packed tower fume-scrubbers for any process; core blowers for short runs or rapid prototyping; core blowers for medium- to high-production with vertically split tooling; process air heaters and super heaters; gassing booths and stations. Gaylord also offers heating and combustion equipment, and layout design/engineering.

Gaylord’s core blowers for medium- to high-volume production with vertically split tooling feature fully automatic, continuous cycle operation. They are completely wired and plumbed for easy installation, and shrouded for fume collection and removal.

Core blowers for short runs or rapid prototyping offer maximum flexibility. They are supplied with ready-to-run horizontal or vertically split tooling made of wood, plastic, or steel. They are fully shrouded for fume collection and safety. They are available in four sizes to meet your tooling requirements.