CNC LATHE / CNC TURNING CENTER

ELECTRICAL DISCHARGE MACHINING (EDM)

With over 100 years combined experience and the latest state-of-the-art software and equipment, HDT’s EDM technicians are among the best in the industry. Our team has provided high quality EDM manufactured products to clients in a variety of major markets including automotive, aerospace, defense, medical, and agriculture to name a few.

Our machine capacity can handle parts ranging from .040” in diameter to 20” x 30” x 14” with the ability to offer surface finish control without compromising structural integrity. The knowledge and expertise of our certified EDM technicians is second to none. Our team looks forward to a challenge and the chance to demonstrate the extraordinary craftsmanship that can be achieved through skilled EDM manufacturing.

Electrical Discharge Machining is an advanced machining technique that allows for precise, detailed cuts that were once thought to be out of reach with traditional machining. Years ago, EDM machining was used mainly for mold-making, however it has now become a crucial part of tool making especially for prototype and production work. With the ability to repeatedly and consistently complete parts with minute tolerances, EDM machining has become the ideal solution for manufacturing parts with unique cuts, angles, tolerances and materials. Materials used in the EDM process must be electrically conductive such as copper, aluminum, bronze, tungsten, carbon steel, high alloy, Inconel, Hastelloy, medical grade stainless steel or carbon graphite.

Header Die & Tool employs three types of EDM technologies in an effort to offer our customers the best solution for their machining needs.

WIRE EDM

The Wire EDM process is achieved by creating an electrical discharge between the wire and the workpiece. A spark is sent from the shortest distance between a single strand of wire, usually brass, and the workpiece where it jumps the gap (known as the spark gap) at which point material is burned away from the workpiece. In order to control the sparking process from shorting out, dielectric, a non-conductive fluid solution is used to either flush or submerge the entire Wire EDM process. The eroded waste material is removed by the continuous flow of the dielectric fluid which is cooled and filter throughout the entire process. Since Wire EDM is mainly used for cutting shapes through assemblies and inserts, it is usually necessary to predrill a hole for the wire to be fed through in order for machining to be completed. The Wire EDM process is utilized only when the required cut goes through the entire workpiece.

BENEFITS OF WIRE EDM

• Precision cuts; Wire EDM accuracy can be within +/- .0003”
• Internal corner cuts with nearly square edges
• Ability to cut long tapers that would otherwise be impossible
• More accurate production & prototype runs with shorter lead times
• Capability to accurately and repeatedly machine delicate & intricate parts with no deflection
• Wire EDM does not generate burrs
• Does not require tooling
• Ability to machine pieces up to 12″
• Machining takes place after heat treatment so dimensional accuracy is not affected by heat treat distortion

CONVENTIONAL or RAM EDM (DIE SINKER EDM)

Conventional EDM is commonly known as Spark EDM. This process is often used when the desired cut or design feature does not penetrate through the entire workpiece. Electrodes for Spark EDM are mostly manufactured from graphite or copper tungsten. RAM EDM electrodes utilize a negative-formed shape which contains all the detail of the final workpiece. Through CNC programming, the electrode is moved along the workpiece, never contacting the piece but creating an area between the electrode and workpiece referred to as Spark Gap. As the electrode moves along the x, y, c, and z axes, complex indentations, shapes, vents and cavities are created. The intricacy that can be achieved with conventional EDM is unmatched by any other method of machining.

Typically RAM EDM applications are performed with the workpiece fully submerged in solution bath. This fluid serves various purposes including flushing away of the eroded material, cooling the heat affected zone and preventing damage to the workpiece, and acting as a conductor between the electrode and the workpiece.

Spark EDM has become a standard method for machining production prototypes due to the precision and abstract cuts allowed by EDM that are not available through alternative machining systems.

HDT electrodes are created through a 4-axis high speed milling process. Our electrodes are milled to completion and incorporate all features of the final product with no hand-scraping required.

Small Hole Drill EDM (Hole Popping)

Small hole drilling EDM machining allows a 0.3mm-6.1mm diameter hole to be drilled through a 100mm piece of soft or hardened steel in about 10 seconds with an average wear rate of 50% to 80%. This process uses a long brass or copper electrode in the form of a tube. The electrode is held in a chuck and rotated as a flow of distilled water flows through the electrode and flushes away the eroded material.

Though small hole drilling EDM was initially used mainly for pre-drilling holes for wire EDM, its uses have since become more widely recognized. Mold and part manufacturing-injection nozzles, oil drain holes, hydraulic cylinders and dowel pins, as well as turbine blades, ball bearings and safety wire holes in hex nuts are just some of the manufacturing areas that benefit from the use of small hole drill EDM.

HDT has found that small hole drill EDM also has a place in venting, small ID work as well as workpieces with small diameters.

COLD HOBBING

HDT has extensive cold hobbing capabilities. We can create customer name, part ID, or grade markings in steel punch inserts by forming the feature instead of machining it. This creates a stronger, longer lasting and better polished finish than conventionally machined or EDM’d producst.

Cold hobbing not only produces a finer detailed product, but in most scenarios, is more cost effective than its EDM’d equivalent.  In addition to the cost benefits, the life cycle of a hobbed part is much longer than that of an EDM’d part.

The process of cold hobbing takes a very hard piece of steel, previously engraved or embossed with specified details, known as the master hob, and pushes it into an unhardened steel blank by way of hydraulic press.  This produces a hob with a reverse image of the specific details either impressed or raised on the blank depending on the job requirement. The pressing process is performed at room temperature with the required pressure varying from 1,380 MPa to 2,760 MPa [200 to 400 X 103 psi] depending on both the hobbing metals and blanking material.  The pressing capacity of large scale hobbing machines may run as high as 2,722 tonnes [3,000 tons].  For the average production hob the pressure needed is much lower.  HDT utilizes a 181 tonnes [200 tons] hydraulic press.  This is more than sufficient pressure for most any production project.  A retaining ring is used to prevent shape deviation or mold spreading.

Master hobs can be used repeatedly and may supply an unlimited number of impressions with great fidelity in size and finish to the hob.  The process of pressing the hob into the blank is known as coining.  Cold-form hobbing is generally done with steel in a fully annealed state.  In order to avoid heat distortion, a cavity in the steel is often the best choice for cold-forming blanks.  In some cases, vacuum –heat treating is done to minimize the need for polishing after heat treatment. This process allows for quick, cost effective part production.

Cold hobbing makes very efficient use of material while producing very strong parts, as the material flows into the desired shapes, maintaining its grain structure.  Traditional machining partially removes grain structure by cutting through portions of the workpiece, truncating sections of the grain and creating vulnerability along all spliced segments.

The cost effectiveness of cold hobbing is apparent in high volume runs. This is because the set up time for cold forming products can be costly, however the time saved when producing a large quantity of parts makes the set up cost well worth it.

STEEL HEADING INSERTS / PUNCHES

With over 125 years combined experience, Header Die and Tool, Inc. steel department manufactures the highest quality steel die inserts and steel punches.  Our skilled craftsmen machine your parts to print on time, every time.  Whether you need assistance choosing the right material for the job, or you need help updating a part to improve productivity, HDT can accommodate you in all aspects of tooling production.

HDT has the capability to both manually turn and CNC machine steel die inserts, punches, and casings with exact consistency of dimensions, from one piece to one thousand pieces.  No job is too big or too small. Our machinists are among the top in the industry with the knowledge and skill to turn even the most challenging concept into reality.

Steel tooling inserts provide a less expensive form of die cast tooling. The high pressure steel tooling inserts are usually consist of enough steel to produce the cavities and a little additional steel to allow for the temperature variations of the molten metal injecting under extreme force. In order to extend the tool life, steel inserts are heat treated to a specific hardness. If the cavity inserts are too hard, the high temperature of the molten metal will cause them to fail and crack the steel. If the cavity inserts are too soft, the injection force of the molten metal will cause early tool wear and erosion.

Quality steel punches can mean the difference between a profitable production run and just barely breaking even.  Tooling that shows early wear, complete failure and overall poor output reduces your efficiency, lowers your quality and eventually affects your repeat business.  HDT has the expertise to manufacture top quality steel punches to exact specifications time after time.  Providing consistent, high-quality tooling on time and under budget is what makes HDT shine above the rest.

Header Die & Tool, Inc. stocks a full line of tool steels allowing us to begin working on most orders the same day they are placed.  This shortens lead times and makes for faster deliveries.

In addition to stocking tool steels, HDT also carries steel nibs in D2, M2, and M42 which are heat-treated and have rough ID’s. Having these pieces on hand gives us the opportunity to fill orders faster as we do not have to wait for outsourcing of the heat-treat process.