Tuesday, January 27, 2009

Tilt Table Bench Top Positioners

Welding around any kind of circular pipe or turning is a tough. Making a smooth fillet weld in the horizontal position, you either have to walk around the work bench, keeping constant arc length if you wish to make a continuous air tight weld. Work like this may be OK if you just need only a few parts welded. Larger batch production runs need positioning devices for higher productivity. The solution is to rotate the work piece with a rotating welding positioners, such as a version called a table or benchtop positioner for small cylindrical parts such as pipe and tubing using a gripper chuck. Bench Top Positioners Source Domestic Built

Welding fabricators need to weld tubing and pipe sections with small jobs and higher production jobs. Tube to elbow, pipe to pipe, and pipe or a flange, all are common welding operations in a fabricating environment. Circular piece like tubes and pipe can be a difficult when rotating. A example, say you want to weld a piece of pipe to a flange. First you tack the two pieces together and clamping the assembly to your work table. To make a weld fillet smooth looking in the horizontal position, you have to move around the welding table, trying to maintain a constant arc length if you want to make a quality weld. One solution to this dilemma is to rotate the work piece past the welding arc with a rotating welding positioner, such as a small to medium-size benchtop machine. Fixed Base and tilt welding table bench top positioners are the answer. Also called Table Rotary Welding Positioners.


Tilting positioners use different tilt options, some use hand wheel for infinite degree of tilt from flat to 90 degrees. Others used fixed set positions of angle, other use a thumb screw nut to allow the tilt positioner a wider range of angles, hand wheel design is the best version on the market today. Of all the defined welding positions, the flat position is the best way to provide the fastest travel speed, highest deposition rate, and best penetration while giving best weld appearance .

If you set your pipe and flange assembly to the welding positioner table, tilt to 45 degrees, you are presenting the joint in the flat welding position. When joining the two pieces of pipe end to end, tilting the positioner to 90 degrees to attain that same flat welding position. This is the most common way pipe sections are joined together with a secondary support.

Benchtop welding positioners typically are rated by the weight they can handle based on center of gravity. The most common sizes are 100, 200, and 250 pound welding table sized positioners. The center of gravity ratings are based on the work piece being centered and balanced on the positioner table. Work weight load is the weldment parts plus fixture used to secure the weldment to the positioner's table or to the tooling or chuck..

Elbow non concentric out of balance loads do not pose a problem when the welding table is in the flat or horizontal position. When a unbalanced load is tilted on a positioner and it speeds up or slows down as the overhung load goes through the 12 o'clock and 6 o'clock position the positioner is under torqued or to small for your job or part. Off set parts often are cause stress on the gear box and motor do to lack or needed torque to maintain constant rotation speed. Securing a weight directly opposite the offending clamp can eliminate this off set load condition, but adds weight and possible problems.

Long parts though perfectly balanced, can cause a problem when the positioner is tilted. Often exceeding the positioners rated center of gravity. This creates an overhung load that can place a severe stress on the positioner's shaft bearings. Most pipe fabricators use some sort of steady rest or pipe roller stand to support the outboard end, such as a pipe stand with a dual roller head.

Benchtop positioners are powered by geared motors that usually drive the table's shaft via a secondary rotation gear or sometimes on cheaper models a drive belt. Most all bench top welding positioners have forward and reverse variable speed rotation, plus foot control. Some foot petals are on/off others are variable speed design.

Securing small diameter tubes and pipe in a spin lock chucks are the best based on weight and lower center of gravity. If you intend to weld a variety of ongoing jobs with parts with different diameters, spin lock chucks allow you easy self centering of the work piece on the positioner's table. Lathe chucks or scroll design chucks are less expensive but push out the center of gravity do to their size, spin lock chucks have both OD and ID reversible jaws.

Some code welding jobs require argon inert gas back back purging. Inert gas purging from the back side of the arc prevents contamination of the root bead during the welding process. This requirement usually is encountered in mig or tig of stainless steel and other alloys. Some positioner manufacturers offer the option of a hollow table shaft with a means of connecting it to an inert gas supply to facilitate purging. Some table top designs use a large through hole to bring a offset load closer to the chuck or positioner's table center of gravity.

If you are considering a bench top positioner, be sure it has an a grounding lug system for return welding current to your welding machine. A capacity of 250 amps or most often needed and a standard on domestic produced positioners. Be sure to attach the ground lead of your welding machine to the stud on the side of the positioner before you start any welding. Welding on a positioner table that is simply bolted to a grounded steel bench will cause welding current to flow through the machine.

Some welders have devised ways to automate entire welding processes using a benchtop positioner as the centerpiece of their automated welding system. When designed and assembled correctly, rack-mounted torches, mounted to the turntable, and micro switches or timing devices can lead to a welding system that requires only loading of the part and pressing a start switch. This requires a less skilled operator, not a skilled welder saving you labor costs. This is a example of a welding automation circle welder using a torch stand and a bench top positioner much like a simple welding lathe.



Check to see if your bench top positioner has a hand wheel tilt feature, ask is it built in the USA. Some positioners are private labeled and imported from China or Japan. If the positioner breaks how quickly can you get parts? Be sure to ask about the warranty and where you can buy parts if needed. Ask if the positioner's control can be upgraded if you wish to automate your welding application. Some of the once domestic produced table positioners are now made over seas. Brand like Jetline, Pandjiris, MBC and MK are still manufactured right here in the USA and offer durability at a affordable price.

Our favorite stocking source for bench top positioners is Weld Plus Inc. in Cincinnati, Ohio There you will find knowledgeable people to help you in your purchase of the proper size USA built table top positioner.

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