Services at G&S Stainless

CNC Plazma Cutting

All our profiling machines can accept cutting profiles in AutoCAD DXF format, or the profiles can be created on site if necessary. All parts are de-burred and can be folded, welded and spray painted as required.

What is CNC Plazma Cutting?

Plasma cutting with the aid of CNC (computer numerically controlled) machinery. Manufacturers build CNC cutting tables, some with the cutter built in to the table. The idea behind CNC tables is to allow a computer to control the torch head making clean sharp cuts. Modern CNC plasma equipment is capable of multi-axis cutting of thick material, allowing opportunities for complex welding seams on CNC welding equipment that is not possible otherwise. For thinner material cutting, plasma cutting is being progressively replaced by laser cutting, due mainly to the laser cutter's superior hole-cutting abilities.

A specialised use of CNC Plasma Cutters has been in the HVAC industry. Software will process information on ductwork and create flat patterns to be cut on the cutting table by the plasma torch. This technology has enormously increased productivity within the industry since its introduction in the early 1980s.

In recent years there has been even more development in the area of CNC Plasma Cutting Machinery. Traditionally the machines' cutting tables was horizontal but now due to further research and development Vertical CNC Plasma Cutting Machines are available. This advancement provides a machine with a small footprint, increased flexibility, optimum safety, faster operation, energy efficiency, ergonomic and more environmentally friendly.

CNC Press Brake Folding

What is CNC Press Brake Folding?

Press brakes and bending machines are used to bend and fold metal by pressing it into a die. There are several types of press brakes and bending machines. Examples include a hydraulic press brake, folding equipment, bending machine, press brake tooling, CNC brake press, and a sheet metal press brake. A hydraulic press brake is designed for both specialized sheet metal work and continuous production applications. A hydraulic press brake is designed to handle tough industrial production jobs from single-cycle operations to automated cell components. Folding equipment can be used to stiffen new metal panels that would otherwise flap around, and to put lips on pieces of sheet that would normally need screws passed through the front face. A bending machine forms angles in sheet metal. Press brake tooling is used in cold-forming metal sheets or strips into desired sections. A CNC brake press is a computer numerically controlled, fully automated brake press with extensive bending capacity and networking function. A sheet metal press brake is used to bend and form sheet metal. Other press brakes and bending machines are commonly available.

Press brakes and bending machines have a variety of functions and specifications. A hydraulic press brake utilizes electrohydraulic control that is based on linear measurement and a control system, which provides reliable, accurate operation in sheet metal work. A press brake manufacturer offers options on a hydraulic press brake including hydraulic clamping, CNC crowning, adapters for European or other style tooling, robot interface, work area illumination, cooler for hydraulics and electrical cabinet over +30 °C, +85 °F, light curtains, and a special voltage transformer. Folding equipment is available with a variety of specifications including a 2160 x 1500 x 2mm capacity. Folding equipment is also available with other features such as backlash free servo gear motors that provide better accuracy and 30% higher speeds, dual drive tool changer, automatic clamp folding tools with integrated tab, offline tools, and fast infeed and outfeed systems. A bending machine can bend sheet metal to almost any angle. A bending machine integrates cells of right angle shears, laser cutters, turret punch/presses and bending units to form a seamless system. The bending machine cells can load, scrap, remove, sort and stack. The overall bending machine system can load and stack sheets, look after component stack buffering, provide cell to cell transfer, and remove bent components. Press brake tooling is utilized to eliminate marking aluminum, stainless steel, and precoated steels during bending, Press brake tooling includes markless tooling film, markless bottom tools and adiprene blocks used as universal bottom tools. A CNC brake press controller is an input/output device into which an operator keys in machine coordinates (ram and back gage locations) and the controller will then position the axes according to those coordinates. Press brakes and bending machines are designed and manufactured to meet most industry specifications

 

Passivation

What is Passivation?

According to ASTM A 380, passivation is “the removal of exogenous iron or iron compounds from the surface of a stainless steel by means of a chemical dissolution most typically by a treatment with an acid solution that will remove the surface contamination but will not significantly affect the stainless steel itself.”

If left untreated, the result will be premature corrosion and ultimately result in deterioration of the component. Passivation removes all traces of iron present in stainless steel and in addition facilitates the formation of a very thin, transparent oxide film, which protects the stainless steel from “selective” oxidation (corrosion).

TWO STAGE PASSIVATION consists of the following activities:

Stage 1:

De-Greasing with a Caustic based degreaser at 60 - 80 degrees centigrade for 2 - 4 hours.
The waste is usually held for certified disposal.
The system is then rinsed to a neutral pH.
Stage 2:

Passivation with either Citric or Nitric Acid at 10% for 2 hours at 30 – 40 degrees centigrade.
The waste is removed for certified disposal
The system is then rinsed using D.I. water until the conductivity of the effluent is below 10 microsiemens.
THREE STAGE PASSIVATION consists of the following activities:

Stage 1:
Alkaline Chelation

Stage 2:
Acidic Chelation with Applied Reductants

Stage 3:
Passivation with Chelating Agent (Proprietary Product)

Electroplating / Electropolishing

What is Electroplating?

Electroplating is a plating process that uses electrical current to reduce cations of a desired material from a solution and coat a conductive object with a thin layer of the material, such as a metal. Electroplating is primarily used for depositing a layer of material to bestow a desired property (e.g., abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities, etc.) to a surface that otherwise lacks that property. Another application uses electroplating to build up thickness on undersised parts.

The basic mill plate and sheet metal finishes for stainless steel include five grades that have finishes that are produced mechanically by using abrasive compositions and buffing wheels.

Special mechanical polishing procedures are required for preparing metal surfaces, such as stainless steel, for electropolishing.

What does Polishing do?

Polishing is an intermediate step used to improve the surface finish from the grinding step, such as found on a common household stainless steel sink - lustrous, but not mirror-like. Polishing uses abrasives firmly attached to a flexible backing, such as a wheel, belt or orbital motion tool.

Mechanical stainless steel polishing is an abrading operation used to remove or smooth grinding lines, scratches, pits, mold marks, parting lines, tool marks, stretcher strains, and surface defects that adversely affect the appearance or function of the part.

The process causes some plastic working of the surface as metal is removed. A mechanically polished surface yields an abundance of scratches, strains, metal debris and embedded abrasives, and always distorts the metal surface.

Burnishing metal by lapping or buffing decreases the micro-inch roughness and improves the image-defining quality of a surface, but it never completely removes the debris and damage metal caused by mechanical polishing.

Mechanical Polishing vs. Electropolishing
Mechanical polishing and buffing cannot be viewed as an adequate substitute for electropolishing. The reasoning for this is due to most applications having embedded abrasives, compounds, exposed grain structure of the metal, the lack of the non-particulating, non-contaminating, and non-outgassing characteristics of an electropolished surface.

Key point:

Any mechanically produced surface (ground, polished, buffed, lapped, honed, etc.) produces a work hardened, disturbed and damaged grain layer approximately 0.001 inch thick. This is accompanied by a scratched, sheared, and torn surface contaminated with embedded abrasives and compounds. Its importance depends on its application. From a cosmetic appearance standpoint, these effects may be unimportant. For high purity applications, e.g., semiconductor or pharmaceutical, particles and contaminants can be of utmost importance affecting purity of product and yield. Often it takes a SEM photomicrograph at very, very high magnification to show these effects - but it is there. A desirable alternative to be considered is electropolishing.