Plasma cutting

Apr 20, 2010 at 09:19 o\clock

Miller plasma cutters can cut through metal

by: sanben   Keywords: plasma, cutters

The Plasma Cutting Machine of the invention includes a constant height plasma arc cutter, a rolling table and a plasma cutter carrying gantry driven from opposite sides. The rolling table is rolled from a loading position where metal sheets are positioned thereon to a cutting position beneath the plasma arc cutter. The plasma arc cutter is held at a constant height above the rolling table. Each metal sheet loaded onto the rolling table is supported on adjustable pins. The entire cutting area is enclosed and vented. The plasma cutter and the rolling table are supported by the cutting system support. A cutter housing supports a transparent curtain, and the transparent curtain encloses the plasma arc cutter. A gantry is supported by the cutter housing, and the gantry supports the plasma cutter. The rolling table includes a table frame, adjustable pins and table wheels. The adjustable pins and the table wheels are connected to the table frame. The adjustable pins extend above and below the pin engaging portion of the table frame. The plasma arc cutter includes a plasma arc cutter member and a cutter positioner. The plasma arc cutter member includes a plasma arc cutting portion and a programmable cutter control. The cutter positioner includes a cutter support and a programmable cutter position controller. The cutter support includes a gantry and a rotatable pinion at each end of the gantry.

Miller plasma cutters use a combination of electricity and air pressure to create a stream of plasma that can cut through metal. There are two different categories of Miller plasma cutters: those with built-in air compressors and those without. A plasma cutter with a built-in air compressor has the added convenience of portability, but does not have the cutting capacity of the larger external air compressor models. Both types of plasma cutters use similar controls for amperage and airflow.Read the operating manual for the model of Miller plasma cutter you intend to use to become familiar with the plasma cutter's controls.

This invention relates to a plasma cutting system of improved efficiency and safety. The improvements of the invention each taken alone or in combination add to operator convenience and productivity and provide equipment portability.

Union Carbide Corporation, Linde Division, Technical Sales Manual, January, 1983 entitled "proDUCTor AUTOMATIC SHEET METAL SYSTEM" discloses a computer aided manufacturing system having two parts, a cutting center and an input control terminal. The cutting center consists of a gantry type machine with microprocessor numerical control, a plasma cutting system, one or more down draft cutting tables and a fume-smoke collector. Plug in the plasma cutter and set the amperage gauge as specified by the chart affixed to the inside of the Miller plasma cutter for the thickness of the metal you are cutting.Remove the cup from the plasma torch and inspect the plasma tip for signs of wear. Replace the cutting tip if you notice large amounts of gouging in the copper tip, and reassemble the torch head.

These problems of the prior art are overcome by the improved plasma cutting system of the present invention. The fume hazards and other loading difficulties of the prior art are either compensated for or not present in a plasma cutting system in accordance with the present invention.The plasma cutting system of the invention includes a constant height plasma cutter, a rolling table and cutting system support. The plasma cutter and the rolling table are supported by the cutting system support. The rolling table is adapted to be positioned on the cutting system support at a loading position at a cutting position. The cutting position is beneath the plasma cutter. Turn on the Miller plasma cutter and secure the scrap piece of sheet metal to a non-combustible firm surface with the self-locking pliers.Put on your leather gloves and tinted safety glasses, and place the copper tip of the plasma torch the distance required by the Miller plasma cutter's operating manual.

In the plasma cutting system of the invention a cutter housing supports a transparent curtain, and the transparent curtain encloses the plasma cutter. A gantry is supported by the cutter housing, and the gantry supports the plasma cutter manufacturer . The rolling table is adapted to be positioned on the cutting system support at a loading position and at cutting position. The cutting position is beneath the plasma cutter. The rolling table includes a table frame, adjustable pins and table wheels. The adjustable pins and the table wheels are connected to the table frame. The adjustable pins extend above and below the pin supporting channels of the table frame. The plasma cutter includes a constant height plasma arc cutter and a cutter positioner. The plasma arc cutter includes a plasma arc cutting portion and a programmable cutter control. The cutter position includes a cutter support and a programmable cutter position controller. The cutter support includes a gantry and a rotatable pinion at each end of the gantry.

Depress the tip of the plasma torch to start the cut. The torch will have a delay, so do not lift the plasma torch away from the surface of the metal.Slowly drag the tip of the plasma cutter along the surface of the sheet metal. Slow down your dragging speed if you notice sparks coming back toward you while you cut; speed up your dragging speed if the plasma arc repeatedly shuts off.The plasma cutting system of the invention optionally includes an additional rolling table. Each rolling table includes adjustable pins supported on transverse channel members.

In the CNC plasma cutting machine of the invention the constant height plasma arc cutter is carried by a gantry driven from opposite sides. The rolling table is loaded in a loading position where the operator positions metal sheets thereon. The operator then rolls the loaded table to a cutting position beneath the plasma arc cutter. The plasma arc cutter is held at a constant height above the rolling table. Each metal sheet loaded onto the rolling table is supported on the adjustable pins. The entire cutting area is enclosed and vented thus protecting the operator from fumes produced during cutting.

 

source:townhall|plasma cutting machine

Apr 20, 2010 at 09:02 o\clock

The glass tube forming proccess

by: sanben   Keywords: tube, forming, machine

FIG. 1A is a side-elevational view of the first two sections of the helical grooving machine with parts broken out to permit illustration of the overall appearance;
FIG. 1B is a side-elevational view of the latter two sections of the helical grooving machine with parts broken out to permit illustration of the overall appearance;
FIG. 2 is an enlarged side-elevational view of the preferred embodiment of the engaging and lifting mechanism of the present invention illustrating engagement of a lifter with a glass Tube forming ;
FIG. 3 is a rear view of the mechanism illustrated in FIG. 2;
FIG. 4 is a plan view of the lifting mechanism illustrated in FIG. 2;
FIG. 5 is a rear view of the positioning mechanism mounted on the upper longitudinal frame of the helical grooving machine;
FIG. 6 is a cross-sectional view taken along the line 6--6 of the mechanism in FIG. 5;
FIG. 7 is a side-elevational view of an alternate embodiment of the engaging and lifting mechanism of the present invention;
FIG. 8 is a cross-sectional view taken along the line 8--8 of the mechanism in FIG. 7;
FIG. 9 is a rear view of the engaging and lifting mechanism illustrated in FIG. 7; and
FIG. 10 is a side-elevational view of another embodiment of the present invention which provides for simultaneous transfer of two glass tubes in tandem from one processing area of the machine to the adjacent processing area.

The subject invention includes an engaging and lifting mechanism for a helical grooving machine for transferring glass tubes from one section of the machine to the next in order for continuous processing operations to be performed on the SBKJ Tube formings in each section. To provide a fuller understanding of the present invention, a brief description of the helical grooving machine and the operations it performs on the glass tubes is provided.

As shown in FIGS. 1A and 1B, the helical grooving machine may be functionally divided into four sections. As the glass tubes are moved from one section of the machine to the next, various operations are performed which result in a finished product when the tubes leave the machine. A left to right flow is described but, of course, the flow can also be in the opposite direction. The first section of the machine is the loading area. This is the input end of the machine into which thin wall glass tubes of circular cross section are placed. The next section of the machine is the preheating area where the tubes are heated to a temperature sufficient to prepare them for the grooving operation. The third section is the grooving area where the glass tubes are subjected to the grooving operation while they continue to be heated in a manner similar to that in the preheating area. In the embodiment of the machine to be described, a helical grooving operation is performed, but any suitable type of grooving can be accomplished. The final section of the machine is the unloading area where the grooved glass tubes are received and from where they are transferred, for example, to a packing area. This general arrangement is shown in the machine of the aforementioned patent. In general, it can be assumed that the Spiral Tubeformers are manually placed on the loading area, and removed from the unloading area. Of course, a conveyor arrangement can be provided, if desired. It should be noted that the grooving machine operates simultaneously on a plurality of glass tubes which are aligned in parallel. The grooving machine of the subject invention operates on sets of four parallel aligned glass tubes simultaneously. Although the following description of the invention relates, in some instances, to the processing of a single glass tube, similar operations are taking place on all the other glass tubes of the set with which the single tube is aligned.

In the preheating area of the machine, gas burner preheaters are supported on the framework and extend longitudinally thereof below the plane of carriage travel. Open top casings 188 enclose the preheaters, which are not shown. There is one preheater, or a group of preheaters, for each glass tube of a set to be processed. In the case illustrated, there are four tubes processed simultaneously, so there are four, or four sets, of preheaters. Supported at the top of each casing 188 are pairs of rotatable rollers (not shown) spaced to support each of the glass tubes T and provide an elongated channel through which heat can be transferred to the lower exposed surface of each of the glass tubes T. This is also described in detail in the aforementioned patent.

Hoods 198 extend along the top of the casings 188, and are supported on the carriage assembly by tubular members 197. By reason of their support from the carriage assembly, hoods 198 travel with the carriage assembly longitudinally of the tube T and casings 188. The preheaters operate as the carriage is moving from right to left during the time that the grooving operation is being performed. The Square Duct tubes are preheated to a point where they still maintain rigidity in the longitudinal direction, so that they can be transferred without any sag of the glass.

The portion of the carriage used in the grooving area is at this time located at its furthest right hand position abutting pusher head 352. On the return trip of the complete movable carriage assembly to the left, the portion of the carriage carrying the grooving apparatus will perform the grooving operation on the glass tubes in the grooving area of the machine. At the same time, the tubes in the preheating section are heated. To return the complete carriage to its starting (left) position so that the grooving operation can be performed by the grooving apparatus as the carriage travels to the left, air is admitted into cylinder 350, causing its piston rod to extend. As should be apparent from FIG. 1A, there is some overtravel to the right for the carriage beyond the tubes T in the grooving area. This permits the flames for the various torches to be turned on. Through the engagement of pusher head 352 attached to the piston rod and an engaging bracket on the grooving carriage, the carriage is returned to its starting position to the right of the tubes in the grooving area, for the grooving operation. At this point lead screw 242 is actuated and engages a half-nut on the movable carriage assembly, causing it to move to the left at a predetermined speed with respect to the speed of rotation of the glass tubes T in the grooving area. Flames from the torches on the grooving carriage soften the glass tubes along the desired path, preferably helical, to form the grooved tube illustrated in the unloading area of FIG. 1B. The carriage speed to the left is usually lower than the speed of the carriage to the right during transfer of the Tube forming machine .

The portion of the carriage used in the grooving area is at this time located at its furthest right hand position abutting pusher head 352. On the return trip of the complete movable carriage assembly to the left, the portion of the carriage carrying the grooving apparatus will perform the grooving operation on the glass tubes in the grooving area of the machine. At the same time, the tubes in the preheating section are heated. To return the complete carriage to its starting (left) position so that the grooving operation can be performed by the grooving apparatus as the carriage travels to the left, air is admitted into cylinder 350, causing its piston rod to extend. As should be apparent from FIG. 1A, there is some overtravel to the right for the carriage beyond the tubes T in the grooving area. This permits the flames for the various torches to be turned on. Through the engagement of pusher head 352 attached to the piston rod and an engaging bracket on the grooving carriage, the carriage is returned to its starting position to the right of the tubes in the grooving area, for the grooving operation. At this point lead screw 242 is actuated and engages a half-nut on the movable carriage assembly, causing it to move to the left at a predetermined speed with respect to the speed of rotation of the glass tubes T in the grooving area. Flames from the torches on the grooving carriage soften the glass tubes along the desired path, preferably helical, to form the grooved tube illustrated in the unloading area of FIG. 1B. The carriage speed to the left is usually lower than the speed of the carriage to the right during transfer of the tubes. The carriage assembly then proceeds to the right so that each carriage section moves the length of two tubes. The shafts 51 and 49 are rotated in the opposite direction so that the tubes are lowered down onto the station and the lifters are disengaged. In this embodiment, the shaft 51 is then rotated in the direction needed to raise the lifters vertically so that they will clear the tube former machines as the carriage assembly moves to the left to perform the grooving operation. After the carriage is at the leftmost position, the shaft 51 is rotated to lower the lifters so that they will be in a position to engage the tubes when the shaft 49 is rotated. Once the engagement takes place, the shaft 51 is again rotated to lift the tubes clear of the top surface of the machine.

As should be clear, the lifting arrangement of FIG. 10 can double the processing speed of the lamps. This, of course, is a decidedly advantageous result.

As should also be apparent, in each of the embodiments of the invention, the lifters do not engage the outside of a glass tube at points where they make contact. Instead, contact is made on the inside of the tube thereby preventing any unnecessary scratching of the tube, and also considerably simplifying the design of the lifters.

 

source:townhall|tube forming machine

Apr 14, 2010 at 07:34 o\clock

How to make glass tubes?

by: sanben   Keywords: tube, forming, machine

FIG. 1A is a side-elevational view of the first two sections of the helical grooving machine with parts broken out to permit illustration of the overall appearance;
FIG. 1B is a side-elevational view of the latter two sections of the helical grooving machine with parts broken out to permit illustration of the overall appearance;
FIG. 2 is an enlarged side-elevational view of the preferred embodiment of the engaging and lifting mechanism of the present invention illustrating engagement of a lifter with a glass Tube forming ;
FIG. 3 is a rear view of the mechanism illustrated in FIG. 2;
FIG. 4 is a plan view of the lifting mechanism illustrated in FIG. 2;
FIG. 5 is a rear view of the positioning mechanism mounted on the upper longitudinal frame of the helical grooving machine;
FIG. 6 is a cross-sectional view taken along the line 6--6 of the mechanism in FIG. 5;
FIG. 7 is a side-elevational view of an alternate embodiment of the engaging and lifting mechanism of the present invention;
FIG. 8 is a cross-sectional view taken along the line 8--8 of the mechanism in FIG. 7;
FIG. 9 is a rear view of the engaging and lifting mechanism illustrated in FIG. 7; and
FIG. 10 is a side-elevational view of another embodiment of the present invention which provides for simultaneous transfer of two glass tubes in tandem from one processing area of the machine to the adjacent processing area.

The subject invention includes an engaging and lifting mechanism for a helical grooving machine for transferring glass tubes from one section of the machine to the next in order for continuous processing operations to be performed on the Spiral Tubeformers in each section. To provide a fuller understanding of the present invention, a brief description of the helical grooving machine and the operations it performs on the glass tubes is provided.As shown in FIGS. 1A and 1B, the helical grooving machine may be functionally divided into four sections. As the glass tubes are moved from one section of the machine to the next, various operations are performed which result in a finished product when the tubes leave the machine. A left to right flow is described but, of course, the flow can also be in the opposite direction.
The first section of the machine is the loading area. This is the input end of the machine into which thin wall glass tubes of circular cross section are placed. The next section of the machine is the preheating area where the tubes are heated to a temperature sufficient to prepare them for the grooving operation. The third section is the grooving area where the glass tubes are subjected to the grooving operation while they continue to be heated in a manner similar to that in the preheating area. In the embodiment of the machine to be described, a helical grooving operation is performed, but any suitable type of grooving can be accomplished. The final section of the machine is the unloading area where the grooved glass tubes are received and from where they are transferred, for example, to a packing area. This general arrangement is shown in the machine of the aforementioned patent. In general, it can be assumed that the Square Ducts are manually placed on the loading area, and removed from the unloading area. Of course, a conveyor arrangement can be provided, if desired. It should be noted that the grooving machine operates simultaneously on a plurality of glass tubes which are aligned in parallel. The grooving machine of the subject invention operates on sets of four parallel aligned glass tubes simultaneously. Although the following description of the invention relates, in some instances, to the processing of a single glass tube, similar operations are taking place on all the other glass tubes of the set with which the single tube is aligned.

Referring now to FIG. 1A, the loading area of the helical grooving machine will be described in detail. This section includes a table 10 having a plurality of U-shaped channels 12 secured to the upper horizontal surface of the table to insure the proper positioning of glass tubes T for subsequent movement into the preheating zone. As illustrated in FIG. 1A and 3, U-shaped channels 12 extend longitudinally of the loading area. The engaging and lifting mechanism and the positioning mechanisms which are both mounted on the upper frame of the helical grooving machine above table 10, will be described in detail below.

The movable carriage assembly extends approximately the length of three sections of the machine. The carriage is divided into three parts. The first part transfers tubes from the loading to the preheating area, the second transfers tubes from the preheating to the grooving area, and the third transfers Tube forming manufacturer   from the grooving to the unloading area. The third part of the carriage also carries the necessary equipment to perform the grooving operation. The three parts or sections of the carriage assembly move and operate in common to provide continuous processing of the lamps. In essence, sets of lamps are transferred sequentially from one area of the machine to the next.

In the preheating area of the machine, gas burner preheaters are supported on the framework and extend longitudinally thereof below the plane of carriage travel. Open top casings 188 enclose the preheaters, which are not shown. There is one preheater, or a group of preheaters, for each glass tube of a set to be processed. In the case illustrated, there are four tubes processed simultaneously, so there are four, or four sets, of preheaters. Supported at the top of each casing 188 are pairs of rotatable rollers (not shown) spaced to support each of the glass tubes T and provide an elongated channel through which heat can be transferred to the lower exposed surface of each of the glass tubes T. This is also described in detail in the aforementioned patent.

Hoods 198 extend along the top of the casings 188, and are supported on the carriage assembly by tubular members 197. By reason of their support from the carriage assembly, hoods 198 travel with the carriage assembly longitudinally of the tube T and casings 188. The preheaters operate as the carriage is moving from right to left during the time that the grooving operation is being performed. The tubes are preheated to a point where they still maintain rigidity in the longitudinal direction, so that they can be transferred without any sag of the glass.Referring to FIG. 1B, heating assemblies 288 corresponding to those in the preheating section, are supported by the machine framework. Here again, there is one heater for each Spiral Tubeformer to be processed. Hoods 298 operate in association with heaters 288.

A carriage 22, shown in the loading area of FIG. 1A, of the movable carriage assembly, supports the engaging and lifting mechanism of the present invention. The portion of the movable carriage assembly for supporting the torches that form the grooves in the outer walls of the glass tubes T during the spiral or helical grooving operation in the grooving area, is not shown. The carriage carrying the grooving torches does not form part of the present invention. Details with regard to its operation may be found in U.S. Pat. No. 3,399,984 to D. G. Trutner, et al.

The unloading area of the machine is illustrated in FIG. 1B. A conveyor 340 transfers completed tubes received from the grooving area along a path perpendicular to the longitudinal path of travel of the SBKJ Tube forming .An air cylinder 350 with pusher head 352 mounted on the end of its piston rod is supported on the machine framework. A bracket (not shown) on the right end of the carriage assembly is positioned to engage pusher head 352. A lead screw 242 operates to return the carriage assembly to the left, to its starting position. This is described in detail below.

 

 

source:freepatentsonline

Apr 14, 2010 at 07:26 o\clock

Proliferation of CNC Plasma

by: sanben   Keywords: CNC, Plasma, cutting, machine

The price of computer cycles fell drastically during the 1960s with the widespread introduction of useful minicomputers. Eventually it became less expensive to handle the motor control and feedback with a computer program than it was with dedicated servo systems. Small computers were dedicated to a single mill, placing the entire process in a small box. PDP-8's and Data General Nova computers were common in these roles. The introduction of the microprocessor in the 1970s further reduced the cost of implementation, and today almost all cnc plasma cutter use some form of microprocessor to handle all operations.

The introduction of lower-cost CNC machines radically changed the manufacturing industry. Curves are as easy to cut as straight lines, complex 3-D structures are relatively easy to produce, and the number of machining steps that required human action have been dramatically reduced. With the increased automation of manufacturing processes with CNC machining, considerable improvements in consistency and quality have been achieved with no strain on the operator. CNC automation reduced the frequency of errors and provided CNC operators with time to perform additional tasks. CNC Plasma Cutting Machine automation also allows for more flexibility in the way parts are held in the manufacturing process and the time required to change the machine to produce different components.

During the early 1970s the Western economies were mired in slow economic growth and rising employment costs, and NC machines started to become more attractive. The major U.S. vendors were slow to respond to the demand for machines suitable for lower-cost NC systems, and into this void stepped the Germans. In 1979, sales of German machines surpassed the U.S. designs for the first time. This cycle quickly repeated itself, and by 1980 Japan had taken a leadership position, U.S. sales dropping all the time. Once sitting in the  position in terms of sales on a top-ten chart consisting entirely of U.S. companies in 1971, by 1987 Cincinnati Milacron was in 8th place on a chart heavily dominated by Japanese firms.

Many researchers have commented that the U.S. focus on high-end applications left them in an uncompetitive situation when the economic downturn in the early 1970s led to greatly increased demand for low-cost NC systems. Unlike the U.S. companies, who had focused on the highly profitable aerospace market, German and Japanese manufacturers targeted lower-profit segments from the start and were able to enter the low-cost markets much more easily. Recent developments in small scale cnc plasma cutter manufacturer  have been enabled, in large part, by the EMC project (Enhanced Machine Controller) from the National Institute of Standards and Technology (NIST), an agency of the Commerce Department of the United States government. EMC is a public domain program operating under Linux operating systems and working on PC based hardware. After the NIST project ended, development continued, leading to EMC2 which is licensed under the GNU General Public License and Lesser GNU General Public License (GPL and LGPL). Derivations of the original EMC software have also led to several proprietary PC based programs notably TurboCNC, and Mach3, as well as embedded systems based on proprietary hardware. The availability of these PC based control programs has led to the development of DIY CNC, allowing hobbyists to build their own using open source hardware designs. The same basic architecture has allowed manufacturers, such as Sherline and Taig, to produce turnkey lightweight desktop milling machines for hobbyists.

Eventually the homebrew architecture was fully commercialized and used to create larger machinery suitable for commercial and industrial applications. This class of equipment has been referred to as Personal CNC. Parallel to the evolution of personal computers, Personal CNC plasma cutting machine has its roots in EMC and PC based control, but has evolved to the point where it can replace larger conventional equipment in many instances. As with the Personal Computer, Personal CNC is characterized by equipment whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user, often without professional training in CNC technology.Although modern data storage techniques have moved on from punch tape in almost every other role, tapes are still relatively common in CNC systems. This is because it was often easier to add a punch tape reader to a microprocessor controller than it was to re-write large libraries of tapes into a new format. One change that was implemented fairly widely was the switch from paper to mylar tapes, which are much more mechanically robust. Floppy disks, USB flash drives and local area networking have replaced the tapes to some degree, especially in larger environments that are highly integrated.

The proliferation of CNC led to the need for new CNC standards that were not encumbered by licensing or particular design concepts, like APT. A number of different "standards" proliferated for a time, often based around vector graphics markup languages supported by plotters. One such standard has since become very common, the "G-code" that was originally used on Gerber Scientific plotters and then adapted for CNC use. The file format became so widely used that it has been embodied in an EIA standard. In turn, while G-code is the predominant language used by CNC plasma machines today, there is a push to supplant it with STEP-NC, a system that was deliberately designed for CNC, rather than grown from an existing plotter standard.

While G-code is the most common method of programming, some machine-tool/control manufacturers also have invented their own proprietary "conversational" methods of programming, trying to make it easier to program simple parts and make set-up and modifications at the machine easier (such as Mazak's Mazatrol and Hurco). These have met with varying success.

A more recent advancement in CNC interpreters is support of logical commands, known as parametric programming (also known as macro programming). Parametric programs include both device commands as well as a control language similar to BASIC. The programmer can make if/then/else statements, loops, subprogram calls, perform various arithmetic, and manipulate variables to create a large degree of freedom within one program. An entire product line of different sizes can be programmed using logic and simple math to create and scale an entire range of parts, or create a stock part that can be scaled to any size a customer demands.Modern CNC mills differ little in concept from the original model built at MIT in 1952. Mills typically consist of a table that moves in the X and Y axes, and a tool spindle that moves in the Z (depth). The position of the tool is driven by motors through a series of step-down gears in order to provide highly accurate movements, or in modern designs, direct-drive stepper motors.

As the controller hardware evolved, the mills themselves also evolved. One change has been to enclose the entire mechanism in a large box as a safety measure, often with additional safety interlocks to ensure the operator is far enough from the working piece for safe operation. Most new CNC plama cutting machine built today are completely electronically controlled.

CNC-like systems are now used for any process that can be described as a series of movements and operations. These include laser cutting, welding, friction stir welding, ultrasonic welding, flame and plasma cutting, bending, spinning, pinning, gluing, fabric cutting, sewing, tape and fiber placement, routing, picking and placing (PnP), and sawing.

 

 

source:townhall|plasma cutting machine