Additional services and supplier management

Raw materials purchasing

Hamavlet has instituted effective purchasing procedures to ensure quality, just-in-time supply, and cost-effective manufacturing. Managing multiple manufacturing projects concurrently, each using different metals, requires efficient supplier management and ongoing handling of raw materials. Hamavlet works with leading and reliable metal suppliers that comply with international standards.

When a customer order comes in, Hamavlet calculates the quantity of raw materials required to manufacture the batch. Thereafter, requests for proposals are submitted to qualified suppliers meeting the customer's requirements. The QA department carries out incoming inspections to verify compliance with the customer requirements and the relevant manufacturing standards.

In large series manufacturing, Hamavlet ensures inventory by ordering the total amount required to manufacture the entire series. Efficient production planning ensures just-in-time supply of raw materials needed for maintaining smooth production, by controlling both the timing of the withdrawal and the quantity required to manufacture a batch.

Hamavlet manufactures products from various metals:

• Colored metals: Aluminum, copper and brass (t = 0.02-6.0 mm)
• Steel: Stainless steel (elastic steels), amalgamated steel (soft steel, tool steel) and carbon steel (t = 0.02-5.0 mm)
• Exotic metals: Beryllium copper, phosphor bronze, nickel silver, titanium and nitinol (t = 0.05-1.50 mm)

Heat treatments

Metal machining operations introduce stresses and alter the mechanical properties of raw materials. Heat treatments improve the mechanical and physical properties of the metal (plasticity/elasticity, hardness/brittleness, electrical conductivity), prior to machining or thereafter. Common heat treatments:

• Annealing - Improves the machining capability of metal, preparing it for stamping or metal machining operations. Stamping, as an example of a cold working operation, creates plastic deformations that toughens the material. Therefore the workpiece has to undergo annealing before additional processing can be carried out.
• Normalizing - Treatment for carbon saturated steel carried out prior to hardening the workpiece in order to remove interior stresses
• Hardening - Improving the mechanical properties of the steel, mainly hardness and strength of tooling steel. The brittleness of the material increases as a result of the hardening process and therefore tempering is required after hardening.
• Tempering - Treatment carried out after hardening to reduce the brittleness of the metal.
• Case hardening - Hardening the surface and increasing the toughness of the part. Case hardening is suited to parts that are made of low carbon content steels, and which are exposed to stress and abrasion simultaneously.
• Aging (precipitation hardening) - Increasing the strength of a steel or aluminum product and improving its resistance to corrosion. The treatment is common in the aerospace, maritime, food, chemical and petrochemical industries. Common uses at Hamavlet include aging of PH-4-17 stainless steel and beryllium copper spring contacts.

Surface treatments

Micro blasting

A mechanical and fast method for roughening or cleaning exposed surfaces, large or small. Abrasive particles are sprayed on the workpiece, through a nozzle, using high pressure compressed air. As a result, the surface texture is altered. The process parameters which affect the surface texture can be controlled, including: The type of abrasive media, the size of the particles, and the pressure. Micro blasting at Hamavlet is carried out for the following reasons:

• Preparation for coating and painting – obtaining a uniform surface by removing surface contaminants (Oil, salts, rust)
• Removal of old coating and paint in preparation for re-coating
• Roughening of the surface to obtain a matt finish for decorative purposes
• Functional roughening to increase friction, for example: Aircraft refueling aperture or an ink blanketing clamp
• Preparation for bonding, for example: Increasing the surface area prior to epoxy molding.

Deburring

Die shearing leaves sharp corners and minute protrusions (burrs) on the surface of the workpiece that are not desirable for aesthetic, safety and functional reasons. Burrs hinder welding, soldering, painting or heat treatments.

Deburring breaks sharp edges, removes burrs, and improves the quality and uniformity of the surface. Trommels (drum mixing) and industrial deburring vibrators are widely used in the metal machining industry. The parts are put into the receptacle together with the abrasive media. Rotation or vibration creates friction between the abrasive particles and the parts, polishing the parts and removing burrs.

Surface grinding

Surface grinding is integral to die manufacturing, renovation and maintenance processes, because the performance of the die depends on the surface quality and uniformity of its parts. To achieve that, the workpiece, which is made of hard metal, is magnetically attached to a portable work bench and passed under a diamond grindstone a number of times.

Coatings

Coating improves mechanical and physical properties of metal, such as: Corrosion resistance, abrasion resistance, hardness, friction, preparation for welding, or electrical properties as conductivity and magnetism. Coating penetrates the product surface, in contrast to painting, which does not penetrate the surface. An additional round of metal coating includes: Preparing the surface for painting, preparing the material as a basis for soldering and imparting a hue to the material. Selective coating can be done at critical points of the system to improve electrical conductivity (gold coating), as a basis for soldering (tin coating) or for other purposes.

Hamavlet cooperates with the leading coating companies in the industry and adapts the type of coating to the product requirements. The metal machining industry uses a number of coatings for a variety of purposes. Following are the most common:

• Stainless steel passivation: Removes iron particles and oxides from the surface and thereby improves corrosion resistance.
• Tin: Used as a basis for soldering electronic components or improving electrical resistance for purposes of electromagnetic shielding. The coating is available in matt or glossy forms.
• Nickel: Used as a basis for silver or gold coating and as an aesthetic element. The coating is carried out without the use of electrical current. The nickel particles bond strongly to the metal surface. The coating also penetrates into hidden areas of the material.
• Gold: Improves electrical conductivity and imparts resistance to corrosion and abrasion to the material. Gold plating is common in the electronics and micro-electronics industries.
• Silver: Similar use as gold plating. An additional advantage - the glossy hue is also used as a light reflector.
• Anodize: Suited mainly to aluminum amalgams and is used as a basis for painting or for aesthetic reasons. In addition, anodizing improves the resistance of the material to abrasion and corrosion and creates an insulating layer.
• Alodine: A chemical conversion process for aluminum that creates a thin, impermeable layer used mainly as a basis for painting. Alodine also improves the conductivity of the part and the resistance of the material to corrosion.
• Zinc: Suited to iron and steel and used as a basis for painting or lubricating, and to improve the machining capability of the surface. Zinc coating imparts reasonable protection against corrosion, but is not suitable for parts exposed to severe corrosive conditions. Zinc coating is available in black, yellow and white.
• Stainless steel black oxidizing: Used to achieve a matt black finish for decorative purposes. With the addition of oiling, stainless steel black oxidizing protects against corrosion. The coating is suitable for moving parts due to the thinness of the coating layer, for example: light weapons parts.
• Black T: Creates a thin protective layer that protects against rust, corrosion and abrasion. The functional and aesthetic properties suit the manufacture of knives, screws, tools and light weapons.
• Manganese phosphate (Parker): An electro-chemical conversion process, suited for hard steel that forms a thin layer on the product and protects against corrosion and abrasion. Manganese phosphate coating is suitable for coating weapons, knives and tools.

Painting

• Wet painting: Spraying of liquid paint onto a paint undercoat forms a protective coat against mechanical impacts. Wet painting is common in many and varied industrial applications, including: Electronics, electronic packaging and communications.
• Epoxy painting: Spraying liquid epoxy adhesive onto the part forms a protective layer against abrasion, heat and the penetration of liquids and chemicals, for example: Epoxy spraying on printed circuit boards in the electronics industry.
• Electrostatic painting: Spraying paint powder onto the product and melting the powder in an oven. Electrostatic painting creates a strong coat with high resistance to abrasion and corrosion.

CNC machining

A process of machining and shaping the product by removing flakes of material from a block of metal, by means of turning, milling and drilling. Metal machining is performed in advanced CNC machining centers that enable the precision manufacturing of complex models in one machine. Hamavlet uses CNC machining as part of the manufacturing process, mainly for supplementary steps.