by Bill Atkinson
Portable pipe cutting equipment is playing an ever-increasing role in the construction and maintenance of today’s piping systems. As the specifications, materials, and design of these systems have increased in complexity, the need for rapid, accurate, and repeatable on-site cutting performance can be instrumental in reducing costs associated with system creation and management.
The popularity of portable pipe cutting equipment is attributable to our reliance on X-ray and/or ultrasonic testing, and the widespread utilization of automatic welding equipment. As the technology of the welding field has advanced and use of automatic orbital welding equipment has become more prevalent, the need for more precise and dedicated end preparation of tube and pipe has increased accordingly. Previous methods of pipe preparation are no longer acceptable.
Today’s offerings range from small machinery designed to cut and square tubing and microfittings, to that capable of severing and single-point machining large-diameter piping in order to generate compound-weld bevels on heavy-wall pipe. Portable equipment is also available for flange facing, sealing surface finishing, boring, grooving, and turning. Plus, there are thousands of tool bits designed specifically for any cutting result required. Unique applications often warrant special engineering and modification of standard tools for a specific purpose.
With so many options offered, it is beneficial to work closely with an equipment manufacturer to acquire the tools exactly suited to the tube- and pipe-cutting work at hand. Following are descriptions of several fundamental categories of portable pipe cutting equipment and the particular usages of each.
Tubing machines clamp the tube’s OD by means of collets. These machines provide cutoff and/or squaring, while generating perfect, burr-free ends. As an accessory, special collet sets are available to prevent deformation or damage to thin-wall tubing from clamping force. Tools can be either handheld for portability, or bench-mounted for increased stability when used in a production role.
The importance of the tubing cutter/squarer has grown significantly due to the introduction of autogenous welding heads for standard and exotic grades of tubing. Equipment of this type is especially helpful when working with microfittings; machinery can be perfectly matched to your fittings, tubing you are working with, and welding equipment.
Typical end users of this equipment are ideally clean room tubing system construction contractors, as well as piping system design and maintenance personnel in industries such as pharmaceutical, biomedical, chemical, research, and other technological fields requiring consistent high purity and precision in the piping system.
End Preparation Machines
End preparation machines clamp to the pipe ID and bevel the end in preparation for welding. This type of equipment is offered in a wide variety of sizes and clamping ranges. As with the tubing machinery, accessory full-support mandrels are designed to uniformly clamp thin-wall pipe, maintaining the shape and preventing deformation while the cut is executed.
The significance of these machines is the ease and speed by which pipe can be squared or “prepped” for welding. Reliable welds are facilitated with repeatable accuracy, with the added advantage of tremendous timesavings when compared to hand grinding and finishing methods.
Accessories for some ID clamping pipe bevelers include single-point modules that produce complex, compound bevels and counterbores, and tracking modules which provide uniform land thickness on out-of-round pipe. A variety of cutting bits are available for these machines, producing many different bevels, depending on the welding process being performed.
The split frame pipe lathe or “clamshell” machine employs a split rotary bearing design which can be divided into two or more sections (depending on size). The sections are placed around the outside of an in-line pipe and bolted together. Then rotating cutting heads cut either straight or bevel cuts from the OD inward. Capable of operating in especially tight- or low-clearance situations, these machines are often the only way possible to accurately remove a section of pipe with the area ready for rewelding. Whether in a confined area, or close to a wall, elbow, or tee, these machines clamp onto in-line pipe and produce precision rotary severs and bevels, making them the ideal choice for maintenance on existing piping systems.
Because this type of equipment clamps completely around the OD of the pipe with clamp pads and jackscrews, the split-frame lathe provides a very stable and secure clamp-up when a cut demands the highest level of accuracy. Complex bevels and counterbores can be machined on small to very large, heavy-wall pipe; and where avoidance of contamination is important, these machines produce minimal chips in the pipe.
In addition to the tools already mentioned, several types of specialty pipe-cutting equipment are currently manufactured. Orbital torch-based units cut pipe with flat or beveled flame-cut-end roller cutters (essentially large, powered versions of the customary hand-tubing cutter found in a plumber’s tool kit). Various pipe saws can be either bench-mounted for production purposes, or mobile devices that “crawl” around the pipe guided by their own clamping chain.
Specialty machinery can be standard tools with modifications such as alternative power supplies (pneumatic, hydraulic, or electric), or special mounting brackets or baseplates. Or they can be completely custom-built machines for a unique operation. Often, special maintenance procedures on oversized or one-of-a-kind components require the manufacture of one-of-a-kind machinery.
Cuts that require unique machinery include operations which must be accomplished remotely due to hazardous environments, or those performed at high speed for high-volume productions purposes. In other instances, radioactive piping needing maintenance or removal require that pipe be cut without the production of chips, necessitating a specially-designed tool. Underwater operations or automated operations can also necessitate specialty machinery. Though specialized, some machinery still require secondary operations to produce finished bevels suitable for use with automatic welding.
One of the most important aspects of portable pipe cutting and beveling equipment involves the accompanying tool bits. It is critical that bits be expertly matched to the machinery being used, material being cut, and the cut specifications, in order to deliver the maximum cutting power to the pipe and achieve desired results. Today, thousands of tool bits are available for virtually any cutting possibility. Advancements in tool bit design, material, finish, and grinding techniques provide bits that are much more durable, which means they will cut longer, with better cut surfaces and increased accuracy.
Remember that the best machine in the world is still merely a carrier for the tool bit doing the work. Inferior cutting bits will undermine every strength built into the machine. Like a high performance race car on worn or inappropriate tires, it simply won’t perform.
Optional accessories to the aforementioned equipment perform a wide variety of specialized operations, and extend the functionality of standard equipment considerably. Special cuts such as socket weld removal, boring, hole cutting, or trepanning can be accomplished accurately and efficiently with the proper tools and complementary accessories.
Conditions encountered while working on piping systems determine when and what accessories are needed as well as the type of equipment and the cutting method used. For example: When pipes are found to be out-of-round, wheeled OD or ID tracker accessories can direct the path of the cutting bit, accurately cutting the pipe while simultaneously following the out-of-round shape. Or, in instances where compensation for out-of-round is not enough, pipe clamps can be used in conjunction with cutting tools to correct and reform the pipe while the cut is being performed.
Selecting the Proper Equipment and Service
A wide selection of cutting equipment offers economical solutions to any pipe cutting and beveling requirements regardless of the industry or particular piping system. Most of the portable pipe cutting equipment available on the market today has been designed either to provide time-saving and dependable results, or to perform previously unattainable machining procedures with optimum results. Besides offering new machinery for sale, some equipment manufacturers maintain an inventory of equipment available on a lease or rental basis. In circumstances without long-term or ongoing justification for the purchase of specialized pipe cutting equipment, equipment benefits can still be applied on an as-needed basis. In addition, some equipment manufacturers maintain a staff of field machinists who can perform reliable on-site machining operations as well as hands-on equipment training for your personnel. The advantage of on-site machining services is that the responding field technicians are equipped with machinery determined to be optimal for the project at hand.
Anyone who designs, constructs, and maintains today’s complex and sophisticated fluid management systems can benefit from the many years of development and experience that goes into contemporary pipe cutting equipment design. Portable pipe cutting equipment can significantly improve the costs, reliability, and maintenance efficiency of piping systems, regardless of complexity, application, or the industry involved.