Progressive Die Stamping Terminal Copper Alloy Continuous Strip 0.01mm

Dongguan Changxinda Precision Technology Co., Ltd. has machined custom parts to drawing since 2008. The plant runs 4-axis and 5-axis machining centers, turn-mill combined lathes and precision CNC lathes, employs more than 90 people, and exports 50 to 60 percent of output to industrial buyers in Europe, North America and Southeast Asia. ISO 9001:2015 certified, first article reports with ballooned drawings as standard.

A progressive die feeds a coil of metal through a sequence of stations, each doing one operation, until a finished terminal comes off the end. The part is never handled between operations, so the cost per piece falls sharply with volume and the consistency comes from the tool rather than from the operator. This page covers the die sequence, the copper alloy choice and the burr and plating control that decide whether a terminal works in an automated assembly line.

The Progressive Die Sequence

The station layout is designed together with the part, because a feature that cannot be formed in the strip has to be added as a secondary operation, and that is where cost appears.

• Pilot and pierce: pilot holes are punched first and used to locate every following station, so accumulative error does not build up along the strip.
• Form and bend: bend radii kept to at least one material thickness, with relief cuts so the material does not tear at the bend line.
• Coin and swage: contact areas coined to control the mating face, and swaged features formed without removing material.
• Trim and cut off: the part is separated from the carrier in the last station, with the carrier designed so the part stays supported until the cut is complete.
• In die sensing: miss feed and short feed sensors stop the press before a damaged part can be produced, and the tool is protected from a double blank.

Copper Alloy Selection

• C11000 tough pitch copper: highest conductivity, used for current carrying terminals where spring force is not critical.
• C26000 brass: good formability and conductivity balance, the default for general purpose terminals.
• C5191 phosphor bronze: higher spring retention, used for contact springs that must hold force over many cycles.
• C7025 copper nickel silicon: for terminals that must survive elevated temperature without losing contact pressure.
• Thickness range: 0.15 mm to 2.0 mm, with the alloy and temper chosen together, since a hard temper that will not form is worse than a softer one that creeps.

Burr And Plating Control

A burr on a 0.3 mm terminal is not cosmetic, it is a failure mode in a reel fed assembly machine.

• Burr height held below 5 percent of material thickness on the functional edges, measured with a profile projector
• Die clearance set per station rather than per tool, because the optimum clearance changes with the local feature
• Deburring by tumbling or brushing where the burr allowance is tighter than the die can hold
• Plating: tin, silver, nickel or selective gold, with the plating thickness specified on the contact area and masking on the solder area where required
• Plating adhesion tested by bend and tape test, and contact resistance checked on samples from each lot
• Parts supplied on reels with the pitch and orientation agreed, or loose in bags for manual assembly

Tooling And Custom Options

• Progressive dies built in house, with the strip layout and the station sequence approved by the customer before the tool is cut
• Prototype quantities supplied from a laser cut or a soft tool before the hard tool is committed, so the design is proven cheaply
• Part widths from 2 mm to 80 mm, with multiple parts per strip where volume justifies it
• In die tapping, welding of contacts, and insert molding preparation available as added stations
• First article inspection report with a ballooned drawing and a strip layout marked with the measured features
• Tool maintenance schedule agreed at handover, with the die kept at our plant and serviced on a fixed interval

Volume And Lead Time

• Tool build: 20 to 35 working days from drawing approval, depending on the number of stations
• Sample parts from the hard tool: 3 to 5 working days after tool trial
• Production: 50000 to 2000000 pieces per month depending on strip size and press tonnage
• Recurring orders run on the same press and the same die, so the second year measures like the first
• Material certificates, plating certificates and inspection records supplied with each lot

Questions From Hardware Engineers

Do I need a progressive die for 5000 pieces?

Probably not. At that volume a compound die or laser cut blanks with a secondary form is usually cheaper. We will quote both and tell you where the crossover sits for your part.

Can the terminal be plated only on the contact area?

Yes. Selective plating is done with masking or with a brush plater, and it is common on terminals where gold is needed only at the contact point. The strip layout has to allow for the mask, which is why we ask early.

Who owns the tool?

The customer does, once the tool is paid for. The die stays at our plant for production and maintenance, and it can be shipped to another supplier on request with the strip layout and setup sheet.