IPC-A-610 helps for nicking in the component lead about 1 percent of the diameter. for a 0.6 mm resistor lead that is 0.06 mm, which is thin compared to human hair and sharp compared to point- a serrated jaw leaves.
That single figure shows faults set for people to blame on soldering: a joint that shows open after some thermal cycles, solder that does not reach the lead, and other joints in the row that become cracked at the body after some time of assembly.
In these conditions, damage occurs before iron-on, and it causes a bent joint to fit on the footprint. Lead-look as simple functions in through-hole assembly, which is why it usually gets the least attention.
What actually damages a component lead?
3 points mainly cause damage; high-bending the closet to the body leads to gripping at one point and bending the same lead more than once.
High bending close to the structure applies high strain on the seal where the lead enters into the package. Overaxial resistor that covers the boundary between the ceramic and the anode and wire; on the glass-glass glass diode is glass
Strain causes cracking on the seal, and a cracked seal causes moisture after board shipping.
Lead gripping at a single point causes slow damage. If complete pair plier force causes a narrow contact patch and deforms leads.
Plating breaks at the point, and lead is left through the notch that concentrates stress. During vibration, a notch causes fractures.
Repeated bending work-hardens wire, functioning as a copper alloy, causing yield strength and using up ductility that bends without cracking; the next bend takes high forces and causes lead splits.
industry has applied the IPC-A-610 proper standard for electronic assembly, which helps prevent nicks, deshaping, and damage of not high than 10 percent of the lead’s diameter, width, or thickness, and defines that limit across all 3 quality classes. On a 0.6 mm resistor lead, 10 percent is 0.06 mm. A visible bite mark from a serrated jaw is deeper than that.
How far from the body should the bend start?
Leave about one lead diameter of straight wire between the body and the causing bending, and not more than 0.8 mm. The inside radius of the bend follows the same rule: one lead diameter minimum. Both figures are to keep strain out of the seal.
| Requirement | IPC-A-610 |
| Clearance between the body and the start of the bend | At least 1 lead diameter, and never less than 0.8 mm (0.03 in) |
| Minimum inside bend radius | At least 1 lead diameter |
| Maximum allowable nick, deformation or damage | 10 percent of the lead’s diameter, width or thickness |
Radius is calculated on the inside bend, not externally, so there is a tight bend over a sharp jaw edge failure that also needs a lead-screw design.
The clearance figure is on the floor, and the target on hand-built boards is less because of a bend of about 2 mm from the body, and the extra millimeter costs nothing.
Which jaws should you use for lead forming?
Using a smooth jaw with a parallel process, the jaw’s shape decides whether the closing force is applied to lead; that is a component of the function we can control.
Older pliers pivot on a single point, so the jaws close like scissors, connecting at tips first and opening into V behind the connection point.
Gripping a thin lead in V shows complete closing force comes through one narrow connection line.
Parallel action pliers replaced the single pivot, having a parallel connection, so the jaws are parallel to each other through the complete opening to closing; the lead sits opposite the flat jaw over the length, and the hand pressure is spread over a larger point.
Serrated jaws cause damage, and on plated lead, it is a bad type. It makes us bite, and we want to rust the fastener; accurately, we do not need the component leads.
Components lead to tin-plated, tin gets soldered slowly, and copper alloy below oxidizes fast in air, and copper oxide causes resistance for wetting, so solder does not increase.
Cut through the plating, and we can see the base metal at the point of the joint made.
Plating losses are defined as causing poor wetting in production soldering
• The jaw needed for leadmaking is smooth and parallel and narrow at the tip, reaching lead between two populated components without touching either.
Choosing pliers for lead forming
Normally, the listing is not a stable jaw face, so monitor the product feature. A smooth jaw indicates a flat, non-broken surface, whereas a serrated one shows cross-hatching.
Accurate values cause smooth jaws or flat jaws, so that’s sold for electronic working to general assembly.
• The tip width is a feature of lifting and releasing, and that is to decide whether we can get lead between two seated components. The Maun snipe-nose parallel pliers, from a UK hand-tool manufacturer that publishes the figure, are 2.0 x 1.8 mm at the tip, with smooth faces and a parallel jaw action.
expecting to pay more than the general purchase price from the hardware store. Extra buys jaw facing, not print pattern on platting. If we are forming leads in any volume, a certain lead-formation tool or simple bench jig affects hand pliers for repeatiition and speed and offers the same spacing over batch.
How do you form a lead step by step?
The sequence below is supposed to be an axial part made with a hand, with one 90-degree bend on each lead and standard hole pitch.
First measure spacing, and set the bend distance from the board, not with the eye. Mismatching space forces the lead sideways when sitting, which again adds strain to the body.
Properly grip the lead between the body and the bending point; for this, the jaws hold the straight part, with one lead-diameter body clearance. plier, not a component, gets loaded.
Allow a flat- jaw set radius, not a lever opposite to the tip, that causes a sharp inside radius.
The crossing angle and accurate back are the 2nd bend at the same point and the point where hardening starts.
A body that stands on its side normally shows two bends at different spaces, and the lead is short.
Check the unbroken area and visible flat spot; a notch on the plating is important for checking reverse to 10 percent limit.
Frequently asked questions
Can you bend component leads by hand?
For one-off repairs, give support to the lead close to the body with a fingernail or smooth tool so it does not bend or shift to seal. Hand-bending offers inconsistent radii and spacing, so it’s not the best where many boards need matching.
Do you need a lead-forming tool, or will pliers do?
Pliers are preferred for prototypes, repairing, and small batches and provide control for different positions. The forming tool is best when needing the same spacing over different components since it sets the bend distance mechanically.
Can a component be reused after its leads are straightened?
In some conditions, work as a suspect, strengthening the other work of the same wire that the lead is brittle and any plating effect from the real bend exists.
Does it matter which direction an axial component faces?
For working, no; for inspection and re-working, it is needed, moslty shops fit some marking that reads similarly due to the value getting and the fast-identified fault-populated board.
Conculsion
Make the bend clear, lead diameter at distance from the body so the stain does not follow the seal, and hold the lead having a feature that spreads the load over the flat face. Smooth, parallel jaws do that 2nd job, and they leave the tin plating intact so the joint wets as they need. Both habits cost a few seconds each, and both remove damage that would otherwise indicate long after the board leaves the bench.
