How to Make Dies for Hydraulic Presses

Hydraulic presses are powerful machines capable of performing an array of metalworking tasks. From punching out identical pieces quickly and producing shapes difficult to produce in other ways to producing complex shapes like domes.

To create a die, begin by sawing out its shape from heavy gauge steel or brass stock, which becomes part A on Diagram 3. Next, cut a blank plate to size and back it with either masonite or plexiglass to complete this step.

Types

Die is an integral component of hydraulic presses used for shaping metal into desired forms. Many different kinds of dies are manufactured specifically for use with such equipment and used for various tasks; some dies are designed for single operation per press slide stroke while others can perform multiple tasks at the same time; specialized dies even perform complex processes like embossing or coining.

Simple dies consist of pieces of metal or acrylic cut to form the silhouette of the form to be pressed, available both from various die companies as well as home or shop-made for relatively little cost. They work well for simple forms and may be made using cast epoxy-steel known as Devcon which can be found at most hardware stores and tooling supply houses for less than $5 in 1-pound cans.

Combination dies are designed to perform multiple operations in one press stroke, such as forming and shaping. They're also capable of punching holes. A combination die can save both time and effort while cutting costs significantly; however, these types of dies tend to be more expensive than their single-operator counterparts.

For permanent, reusable dies for your hydraulic press, start with a scale drawing of the desired form. Cut out your die from Lexan--a high density polycarbonate that's shatter resistant. Make the depth equal to that of the metal you plan to press; multiple smaller dies may be required depending on its depth.

Reusable dies can easily press gold, silver and copper sheet metal of 24 gauge to 16 gauge with relative ease. Metal that is thinner may tear, krinkle or crimp when compressed in these basic molds. For thicker metal sheets you will require more complex molds with much higher hydraulic pressure for pressing purposes.

Materials

Hydraulic presses produce significant force. This type of press is commonly utilized for casting pellets, laminating electrodes, punching them out in material science labs as well as metal forming and shaping applications to produce various parts or products such as jewelry ring blanks.

Making dies with a hydraulic press requires using materials suitable for this application and result. Common materials include epoxy-steel, cast iron, hard rubber and pourable epoxy-metal material; your choice will depend on its specific use case and desired results.

Cast iron makes an excellent material choice for metal forming presses, as it can withstand an impressively large amount of pressure while offering greater strength than most other materials. Furthermore, its weldability allows for fast repairs.

Hard rubber and urethane materials are excellent choices for creating dies for use with hydraulic presses, usually at less cost than cast iron and with increased resistance to wear and tear; however, their strength does not match that of cast iron. When selecting material to make dies from, durometer should be taken into account; materials with lower durometer are generally softer and move more freely while higher durometer are harder and more durable.

Devcon material from Devcon Corporation of Danvers, Massachusetts provides an easy and cost-effective solution for producing hydraulic press dies. Available in various sizes for purchase at most hardware stores or tooling supply houses, Devcon can be used to craft tools, jigs, fixtures, metal forming dies and foundry patterns.

An effective process for making dies with a hydraulic press involves creating a model or pattern of your intended product and molding male and female dies that conform to it. Once these dies have been placed in the press, sheet metal is placed between them; pressure from the press then transforms this sheet metal into its desired form.

Techniques

Hydraulic die forming, which works similarly to hammer forming by forcing metal into negative die shapes from one side while exerting positive forms on the other, allows users to form shapes not possible using shears or punches alone. Different kinds of dies can be used, from non-conforming ones using rubber to conforming ones made out of steel; matrix dies are among the most frequently utilized for hydraulic presses as they employ Flexane material that forms desired shapes when cut with a punch; it is reusable thousands of times over its lifespan while different thicknesses make it available for various forming applications.

To create a matrix die, begin by drawing out your desired shape in scale on paper or wax before sticking it to a rigid material, such as steel pipe or plexiglass, and covering it with plasticene to seal against dust. Use the release agent included with a Devcon kit as an adhesive between these elements before sawing or drilling out your pattern from the plate using saws or drills before filing up to the scribed lines, creating part A of your matrix die and known as male die.

Shears can be used in a hydraulic press, however before use the punches must be sufficiently "de-bubbled" and lubricated using silicone or another suitable lubricant to ensure that pins slide easily without binding during shearing action. When not in use the shearing die should be set on a hard surface and all punches removed from it when not required.

To create a permanent and reusable shear die, cut a piece of sheet metal large enough to accommodate both female dies plus about an additional 3/8 of an inch around their outlines. This extra flange will help conform the metal to negative die shape more readily while protecting shears from breaking down over time. When done, cover male die and matrix with Devcon according to instructions included with kit.

Equipment

Hydraulic presses are an excellent way of shaping metal into various forms. They replace traditional hammer forming methods by exerting force from both sides of the die to force metal into an unwanted, restricting shape. Conforming, two-part dies; and non-conforming (silhouette), single shape dies are two general types of dies used today. Both require a matrix for the metal to rest against. When creating a conforming die, begin by modeling its form to produce it accurately. This model could be made of plexiglass, wax, wood, plaster or plasticene and should be at least 3/8-inches larger all around than your desired final product. Edges should be no more than 1/4 inch wide and perpendicular to faces; small details and textures won't appear in your finished product but may be added via chasing later on.

Once the die has been completed, an annealed copper sheet should be laid over the matrix and lubricated with silicone or release agent before cutting out of it with a punch. Care must be taken when filing down this punch to allow space for Devcon when casting takes place - additional space may be needed depending on its gauge thickness and gauge weight; to make room for Devcon, carefully file away around an inch's worth from its edge of the matrix matrix.

Once the dies are prepared for use, it's essential not to over-tighten or damage the punch. Devcon is a low-temperature material which is difficult to handle under pressure; at least four minutes must pass for all the metal to have been completely poured into each mold and for them to separate from each other.

While the basic principles of die forming remain constant, new tools and accessories have emerged to assist with this process. While it would be impossible for this book to cover every development in this field, an internet search for "hydraulic die forming" on YouTube will reveal an abundance of resources as well as demonstrations.