When Does a Filtering Chip Conveyor for CNC Lathes ...

Filtering chip conveyors, such as those used in the production of parts like these at Flotec in Indianapolis, can evacuate virtually all chip materials, sizes, and shapes, while removing particles as small as 50 microns. Photo credits: LNS America

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Shops evaluating potential new CNC milling machines or lathes to purchase typically consider several factors: how well the machines will integrate into existing processes, their capacity and versatility to evolve with the business, their dependability and robustness, as well as the availability of replacement parts, technical services, and customer support.

LNS America asserts that these same considerations should extend to the selection of peripheral machining equipment, such as chip conveyors. These devices can optimize a machining process or become a weak link, depending on their compatibility with current machining applications and their adaptability to future requirements.

Chip conveyors come in various designs and price ranges. Although filtering chip conveyors may require a higher initial investment, their return on investment could justify the expenditure, enhancing the effectiveness of machining equipment for future jobs and materials.

Chip Conveyor Choices

Hinge-belt chip conveyors are among the most popular types and are frequently included with new CNC machine purchases. They are affordable and reliable when properly matched to specific machining applications, such as collecting a mix of coarse and stringy materials. However, they are not the ideal choice for operations producing fine chips of aluminum, brass, cast iron, or other materials. Smaller particles may contaminate coolant and clog the conveyor, fluid lines, and pumps.

Magnetic chip conveyors are suitable for ferrous-only machining processes that create broken chips. Still, if the process generates stringy material longer than the spacing of the conveyor magnets, these long strings can short the magnets. Additionally, using a magnetic conveyor for ferrous materials that create fines is not recommended due to coolant delivery system issues.

When inefficient chip management led to production interruptions, Flotec turned to LNS America for assistance.

Conversely, filtering chip conveyors can evacuate almost all chip materials, sizes, and shapes, while removing particles as small as 50 microns that could potentially damage pumps and reduce coolant life. Furthermore, they can prove effective as shops push machine speeds and feeds to boost productivity and cut costs. This increased production often results in higher temperatures in the cutting zone, necessitating greater coolant flow to manage the heat. In some instances, an uptick in coolant volume can overwhelm a conventional chip conveyor, leading to production slowdowns or stoppages, as well as potential damage to the coolant pumping system. Recirculating chips can also degrade cutting tool life and hinder the surface finish of machined workpieces, which may prevent shops from achieving reliable lights-out production or extending unattended machining times.

Filtering chip conveyors can evacuate virtually all chip materials, sizes, and shapes, while removing particles as small as 50 microns.

Modern machine tools can handle various operations and materials, from aluminum and basic steel to exotic alloys. When new job orders necessitate changes in production processes, a machine's adaptability may be limited by a chip conveyor that can't cope with the increased workload. In such cases, replacing the existing conveyor with a more efficient model may be necessary. The filtering chip conveyor is touted by LNS as the type most capable of effectively managing a broad range of CNC machining challenges, filtering virtually all chip materials, types, and shapes from coarse and stringy to very fine.

What to Look for in a Filtering Chip Conveyor

Several filtering chip conveyor designs are available. Some feature replaceable filter media, while others utilize permanent, self-cleaning filtering drums constructed from stainless steel or other materials, which may also employ scraper systems or perforated box filters.

A filtering chip conveyor can effectively tackle various CNC machining challenges by filtering diverse chip materials, types, and shapes.

Chip conveyors equipped with replaceable, self-cleaning filter boxes greatly reduce maintenance efforts and can be easily modified for different machining applications. For instance, the LNS MH Series filtering chip conveyors have interchangeable filtration boxes capable of eliminating chips as small as 250 microns, while the SF model filters chips down to 50 microns. These conveyors offer hardened tracks, particularly in curves, to minimize wear; reinforced belts for enhanced durability and reduced maintenance; a compact footprint comparable to non-filtering chip conveyors; and customizable discharge points.

Upgrading to a filtering chip conveyor allowed Flotec in Indianapolis to meet increased demand arising from the COVID-19 pandemic. Flotec manufactures regulators and other essential components for medical equipment utilized by hospitals, neonatal ICUs, and EMS services. The company, which began operations in recent years, supplies parts for both OEMs and end users worldwide, with nearly all products custom-made. Its regulator line alone boasts over 4 trillion unique items.

As the coronavirus pandemic spread, the demand for Flotec's products compelled the company to maximize output and rely more heavily on lights-out production for its twin-spindle, twin-turret Swiss-type lathe. Successful overnight production requires a seamless manufacturing process. When inefficient chip management caused interruptions, Flotec turned to LNS for a solution.

The Swiss-type machine was originally fitted with a standard hinge-belt type chip conveyor. However, Flotec utilizes this machine for machining 6061 and T651 aluminum, certain brass alloys, and 303 stainless steel. The process generates very fine chips that passed through the chip conveyor into the recovered coolant, flowing into the coolant tank filtering system.

The machine features four high-pressure filter baskets and an additional basket for capturing fines before they enter the coolant pumps. However, these materials filled the filter baskets, resulting in decreased coolant levels. Simultaneously, chips accumulated in the coolant tank, displacing coolant volume. This volume loss triggered low coolant alarms, leading to reduced coolant flow through the high-pressure delivery system. Consequently, the machined parts and cutting tools experienced insufficient cooling, adversely affecting tool life and part finishes.

To address these issues, LNS replaced the existing hinge-belt chip conveyor with the LNS Turbo MH 250 filtering chip management system. Its self-cleaning filter box design enables the MH 250 to eliminate virtually all sizes and types of chips, including fine aluminum and brass created during Flotec's milling process, while filtering coolant down to 250 microns.

According to Flotec President Brian Davidson, "Before we replaced the original chip conveyor with the LNS filtering model, we were achieving about 75 units of production during the day and 40 when running lights-out overnight. Now, we produce 75 units in a 9-hour day and 125 units from 5:30 PM until 8:30 the next morning. As a result, we've more than doubled the output of this CNC machine from approximately 2,875 monthly production units to 6,000 units simply by replacing the original chip conveyor with the LNS MH 250 filtering chip conveyor."

He added there is less maintenance involved now. "We now clean the coolant tank only once a month. Before switching to the filtering chip conveyor, we cleaned the machine's two filter baskets three to four times per day. Now we only clean them twice weekly. Likewise, we've reduced the high-pressure filter basket cleaning frequency from daily to just once per week."

Flotec also discovered that by preventing fines from displacing and degrading coolant, the high-pressure system can perform effectively, safeguarding critical part finishes, reducing tool wear, and extending coolant life.