Roll-Formed Parts Manufacturing of Micro Components

Roll Forming is an extremely cost efficient method of forming shapes on the outside diameter of round parts. The cycle rates can be very high, many times that of machining.

When looking for a contract manufacturer, keep in mind that roll formed parts can include  these types of shapes and features: narrow or broad undercuts, knurls, pointing, chamfers, grooving, odd surface finishes, collars, special shapes, and threading.

Advantages of roll forming onto your components include:

  • Material savings: Forming a feature by rolling usually creates no waste, since the existing metal is extruded and shaped into the desired feature. Machining will always create waste. Roll forming does not.
  • Strength: Rolling will increase the component strength, very similar to cold forming in this respect.
  • Dimensional consistency: Roll forming is superior; there is no cutting edge that wears away quickly as production progresses.
  • Versatility: Surface finish over the OD of a piece part can be varied; i.e., rough or smooth depending on the need.

Following are several examples of roll-formed parts illustrating attributes of roll formed features.

Example #1: Miniature hermetic seal terminal pin with roll-formed grooves

Description: .040” diameter OD pin manufactured with fully radiused end condition. Material: 52 (Nickel/Iron alloy) controlled expansion alloy with four rolled grooves on OD.

The grooves are designed to create a “retention feature” where the glass (in a glass-to-metal seal) will flow into the grooves, providing a “grab” onto the pin which otherwise would not occur with a straight /smooth pin; pull strength measurements are enhanced because of the rolled “grooves”. The grooves are rolled at a high rate of speed; it is very inexpensive to add a grooved feature in this manner.

Photo: Note the OD is constant over the entire pin length, even across the groove OD.

Example #2: Miniature Headed Copper terminal with rolled knurl

Description: .030” (.32 mm) headed and KNURLED pin; .375” (9.5mm) overall length. Material: CDA 102 (oxygen free, high conductivity).

The knurl is rolled at high speed after cold forming the various OD diameters. The knurl is meant to “push into” a hole in a printed circuit board and maintain a hold before soldering.

Example #3: Miniature Headed Copper terminal with Rolled Threads

Description: 8-32 threaded pin with multi diameters.
Material: CDA 102 (oxygen free, high conductivity).

The threads are rolled in a manner to guarantee no flaking in between the individual threads, and no cracking on the OD of the threads. This feature is especially important since precious metal plating will be applied after forming. The thread rolling operation is high volume and inexpensive.

Example #4: Roll formed undercut on small ball headed valve pin

Description: Multi die formed “ball headed” stainless steel pin with a rolled secondary that produces the (minor OD) “undercut" shape in the middle. The undercut is produced while holding the overall length of the part to +/- .005” (.127 mm).
The major diameter is rolled into the minor diameter for a 48% reduction in cross sectional area.

Example #5: Rolled chamfers on Micro sized component

Description: .0120” (.3mm) diameter straight pins with rolled chamfers on each end.
Material: Phos Bronze CDA 510.

The challenge with the rolled end condition on this example is the micro-size of the part. The rolled chamfers are clean with no material roll-over and no “hollow concave dimple” condition at the ends.

The part receives precious metal plating after rolling and therefore no dirt/oil/rolled-over material is permissible. Plating will fail because of trapped dirt.

The rolled ends on a high volume piece part are an alternative to “tumbled” pins. Tumbled pins are usually exposed to grinding media and chemical compounds that can be entrapped in the metal surface and create quality issues downstream in assembly/plating.

Example #6: Rolled undercut and rolled chamfer on a thermocouple contact terminal

Description: .200” diameter contact pin that is formed/coined/trimmed and hole pierced and then rolled. The rolling creates the “undercut” area on the main shaft as well as the precisely angled chamfer at the terminal end.

Material: High tensile Nickel alloy that is difficult and costly to machine.

The rolled undercut is a retention feature designed to snap into a mating receptacle. The surface finish is important because a good finish will create less friction as this terminal is pushed into the mating device. The excellent finish in the rolling die requires less maintenance, produces more consistency, and delivers higher production rates versus machining.

Example #7: Rolled undercut on brass connector pin

Description: .710” (18mm) overall length CDA 260 brass terminal with rolled undercut.

Note the nice finish in the undercut area. Part is high volume and is rolled at high speed for a low cost solution.

Example #8: Three diameter pin with roll formed double barb

Description: Three diameters are .094” (2.4mm); .067” (1.7mm); .062” (1.52mm); they are extruded in a cold forming machine.
Material: 4037 steel.

The roll formed “double barb” is at one end of the component and it is notable that the OD of the barbs is .072” (1.83mm), i.e., it is larger than the diameter it is rolled from. This double barb is a press fit retention feature that is very cost effective when compared to the machined alternative.

Example #9: Headed pin with rolled point at one end

Description: Glass-to-metal seal terminal.
Material = 52 alloy (Ni/Fe alloy).

Note: The pointed tip is actually a double tip where the angle of the point changes to a controlled radiused tip at the very end.

Note: The very nice surface finishes produced by rolling the feature—no machine lines present versus a screw machined part.

Example #10: Headed Pins with rolled “Points” at one end

Description: headed pin used as a battery anode.
Material: Brass CDA 260 (leadless brass).

This pin point is used to pierce through various metal layers in the manufacturing of a battery. The point is sharp to a .010” max flat tip configuration.


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