Calculate the approximate weight of equal or unequal angle using leg dimensions, thickness, length, and material.
Actual rolled-angle weights may vary slightly due to corner radii and manufacturing tolerances.
Calculate the approximate weight of flat bar using width, thickness, length, and material.
Convert common inch fractions to decimal inches and millimetres.
Calculate the approximate weight of square or rectangular hollow structural tubing.
Actual HSS weights may differ slightly because manufactured HSS has rounded corners and dimensional tolerances.
Calculate approximate pipe weight using a standard pipe size and schedule, or enter custom outside and inside diameters.
Calculate the approximate weight of a rectangular plate using length, width, thickness, and material.
Calculate the approximate weight of a solid round bar using diameter, length, and material.
When a waterjet cuts through steel, stainless steel, aluminum, or another material, it does not create a zero-width line. The high-pressure water and abrasive stream removes a small amount of material along the cutting path. This removed width is called the kerf.
For example, if the kerf is approximately 0.060 in wide, the cutting process removes about 0.060 in of material along the programmed path.
If a cutting machine follows the exact edge of a drawing without compensating for kerf, the finished part may be slightly too small or too large.
Waterjet cutting software normally compensates for this by moving the tool path slightly away from the finished edge. This is commonly called kerf compensation or tool offset.
Correct kerf compensation helps produce parts that are closer to the required dimensions.
Waterjet kerf can vary depending on several cutting conditions, including:
- Nozzle and mixing tube size
- Material type
- Material thickness
- Cutting speed
- Water pressure
- Abrasive flow
- Nozzle condition and wear
These factors can affect the width and consistency of the cut.
Thicker materials normally require slower cutting speeds. The waterjet stream can also lose some energy as it passes through the material, which can affect the shape of the cut.
This is one reason why the correct cutting speed and quality settings are important when producing accurate waterjet-cut parts.
Kerf taper means the cut may be slightly wider at one surface of the material than at the other.
This can happen because the waterjet stream changes as it travels through the material.
Higher-quality cutting settings can help reduce taper, but they normally require slower cutting speeds.
Waterjet cutting is a cold-cutting process and does not normally create a heat-affected zone in the material.
This can be useful for parts where heat distortion, hardness changes, or thermal damage may be a concern.
Cutting settings and kerf compensation are selected to help maintain dimensional accuracy and produce a clean finished edge.
We can work from supplied drawings or help create CAD and DXF files when required.
MMEF provides CNC waterjet cutting services throughout Edmonton, Nisku, Leduc, and surrounding areas.
Welding distortion is the movement or change in shape of a part caused by heating and cooling during welding.
When a weld is made, a small area of the metal becomes very hot and expands. As the weld and surrounding metal cool, they contract. This contraction can pull the welded parts out of their original position.
The result can be bending, twisting, bowing, angular movement, or changes in the dimensions of the finished assembly.
A simple way to think about weld shrinkage is to imagine a stretched rubber band connecting two pieces of material.
While the rubber band is stretched, it is pulling on both pieces. If the pieces are free to move, the rubber band will try to pull them toward each other.
A cooling weld can create a similar pulling effect. As the hot weld metal cools and contracts, it pulls on the surrounding material.
If the assembly is not balanced or restrained properly, this pulling action can cause the part to bend, rotate, or move out of position.
The rubber band is only a simple comparison, but it helps explain why welds can move parts as they cool.
The main cause of welding distortion is uneven heating and cooling. Some areas of the part become much hotter than others during welding.
Several factors can affect how much distortion occurs, including:
- Amount of heat introduced during welding
- Weld size
- Number and length of welds
- Material thickness
- Joint design
- Welding sequence
- Location of the welds
- Fit-up and tack welding
- Clamping and restraint
Thin materials can be particularly sensitive because they generally have less stiffness to resist movement.
Welding distortion can appear in several different ways depending on the part and weld configuration.
- Angular distortion – the parts rotate or change angle near the weld.
- Longitudinal shrinkage – the material contracts along the direction of the weld.
- Transverse shrinkage – the material contracts across the weld.
- Bowing – a plate or member develops a curved shape.
- Twisting – the fabricated assembly rotates along its length.
More than one type of distortion can occur in the same welded assembly.
Larger welds generally require more weld metal and more heat. As this larger volume of heated material cools and contracts, it can increase the amount of shrinkage in the assembly.
For this reason, welds should normally be made to the size required by the drawing, design, or applicable welding requirements rather than simply making them larger than necessary.
An oversized weld does not automatically make a fabrication better and may increase welding time, material use, heat input, and distortion.
Welding an assembly continuously from one end to the other can allow shrinkage to build in one direction.
Depending on the fabrication, distortion may be reduced by planning the welding sequence so that heat and shrinkage are distributed more evenly.
This can include alternating between different sides of an assembly, welding in shorter sections, or changing the order in which welds are completed.
The best welding sequence depends on the geometry, material thickness, joint design, and fabrication requirements.
Tack welds help hold components in their correct position before final welding begins.
Clamps, fixtures, strongbacks, and other temporary restraints may also be used to help maintain alignment while the welds are being completed.
Good fit-up before welding is important. If parts begin out of alignment, controlling the finished dimensions becomes more difficult.
Restraint should be planned carefully because excessive restraint can increase stresses in the welded assembly.
In some fabrications, parts can be intentionally positioned slightly in the opposite direction of the expected weld movement before welding.
As the weld cools and contracts, the shrinkage may pull the assembly closer to its required final position.
This technique is commonly called presetting or pre-setting.
The amount of preset depends on the particular fabrication and is often based on experience with similar welded assemblies.
Welding distortion cannot always be completely eliminated, but it can often be reduced through proper fabrication planning.
Common methods include:
- Using the required weld size without unnecessary overwelding
- Planning the welding sequence
- Balancing welds where practical
- Using proper tack welds
- Using clamps and fixtures where appropriate
- Maintaining good fit-up before welding
- Controlling heat input
- Allowing appropriate cooling between welds when required
- Presetting components when appropriate
The correct method depends on the material, joint configuration, thickness, weld requirements, and final dimensional tolerances.
Proper fit-up, tack welding, welding sequence, weld size, and dimensional checks are important parts of producing accurate welded fabrications.
Depending on the project, fixtures and clamps can also be used to help maintain the required position of components during welding.
MMEF provides MIG welding and custom fabrication services for brackets, frames, handrails, jigs, fixtures, equipment components, and other fabricated steel parts.
We provide welding and fabrication services throughout Edmonton, Nisku, Leduc, and surrounding areas.