How CNC Machining and Metal Stamping Work Together in Precision Manufacturing

Some parts are too complex for stamping alone. Others would cost too much to machine entirely from solid billet. For a significant number of precision components, the most efficient path to a finished part involves both processes: stamping to create the base geometry at volume, and CNC machining to add features that stamping can't produce.

The challenge is that many manufacturers treat these as separate operations handled by separate shops. That split introduces coordination overhead, tolerance stacking, and lead time problems that a combined approach eliminates.

Here is how integrated stamping and CNC machining works, when it makes sense, and what to look for in a manufacturing partner who can handle both.

Why Do Some Parts Need Both Stamping and CNC Machining?

Metal stamping and CNC machining are fundamentally different processes. Each one excels at things the other can't do efficiently.

What stamping does well:

• Producing flat and formed sheet metal geometries at high volume

• Maintaining tight tolerances across thousands or millions of identical parts

• Creating features like bends, draws, embosses, and cutouts in a single press stroke or progressive sequence

• Keeping per-part costs low once tooling is built

What CNC machining does well:

• Adding threaded holes, precision bores, and complex 3D surfaces

• Machining features that require tighter tolerances than stamping can hold in a specific area of the part

• Creating features on surfaces that the die can't reach

• Producing low-volume parts or prototype quantities without tooling investment

When a part needs formed sheet metal geometry plus machined features, using both processes is often the most cost-effective approach. The stamping die handles the high-volume base geometry at low per-part cost. CNC machining adds the precision features that the part's function requires.

Common examples include brackets with precision mounting holes that need tighter positional tolerances than the stamping process can hold, housings with formed features and machined mating surfaces, electrical components with stamped contacts and machined connection interfaces, and structural parts with stamped geometry and machined fastener locations.

What Happens When Stamping and Machining Are Split Between Two Shops?

Sourcing stamped parts from one shop and machining from another is common. It also creates problems that are easy to underestimate.

Tolerance stacking. Every time a part is removed from one fixture and set up in another, positional accuracy is at risk. When the stamping shop and the machining shop are using different fixtures, different datums, and different inspection equipment, small variations compound. A stamped feature that is within tolerance at the stamping shop may not align correctly with a machined feature at the second shop, because the part is being referenced differently.

Lead time math. Split manufacturing means your part goes through two separate production queues, two separate shipping cycles, and two separate inspection processes. If the stamping shop runs behind schedule, the machining shop's capacity sits idle. If the machining shop has a quality issue, the stamped blanks may need to be re-run before corrections can be verified.

Quality accountability. When a finished part fails inspection, who is responsible? If the stamped geometry is within tolerance but the machined features are off, the machining shop may argue that the stamped datum surfaces were out of position. Resolving these disputes takes time and often requires both shops to re-inspect against their own records.

Communication overhead. Two separate sets of purchase orders, quality requirements, material certifications, and shipping logistics. Every drawing revision has to be communicated to and acknowledged by both shops. For parts in regulated industries where documentation traceability matters, managing two quality records instead of one adds administrative burden.

How Does Single-Source Manufacturing Solve These Problems?

When stamping and CNC machining happen in the same facility, most of the problems described above go away.

One engineering team reviews the full part. Instead of splitting the print between two shops, a single engineering team evaluates both the stamped and machined features together. They can design the stamping die so that formed features serve as reliable datums for the machining operations that follow. This is a significant advantage that is difficult to achieve when two separate shops are working from the same print independently.

Fixturing designed for both operations. The machining fixtures can be built to reference the actual stamped features, not theoretical dimensions from the drawing. This eliminates one of the biggest sources of tolerance stacking in split manufacturing.

No shipping between facilities. Parts move from the stamping press to the CNC department without leaving the building. There is no transit time, no packaging and unpacking, no risk of handling damage, and no second shop queue to wait in.

One quality system. A single inspection process, a single set of material certifications, and a single point of contact for quality questions. For customers in aerospace, defense, or medical device manufacturing, dealing with one quality record instead of two simplifies compliance documentation.

At Jennison, our precision metal stamping and CNC machining operations share the same facility in Carnegie, Pennsylvania. Parts that need both processes move between departments without leaving our building.

What CNC Machining Equipment Supports Integrated Manufacturing?

The range of machining work a facility can handle determines which parts it can finish in-house versus which ones require outside processing.

Our CNC department operates 18 machining centers running 24 hours a day. The equipment includes:

• Vertical machining centers for parts up to 50" x 26" x 25", including a Haas VF5SS with 30 HP and 12,000 RPM spindle speed

• Horizontal machining centers for complex multi-sided work, including a Mori Seiki NH5000 with 14,000 RPM and a Daewoo with 10,000 RPM

• Live tooling lathes and turning for rotational features up to 32.7" in diameter

Beyond CNC, we also operate wire EDM for features that require tight internal corners or cuts through hardened materials, and a 1500W fiber laser system for flat profiling and cutting.

This range of equipment means most parts that need both stamping and machining can be completed entirely in-house. The fewer outside operations a part requires, the shorter the lead time and the simpler the quality documentation.

Which Industries Benefit Most From Combined Stamping and Machining?

Any industry that uses precision sheet metal components with machined features benefits from integrated manufacturing. A few sectors see the most impact.

Aerospace. Parts often require both formed sheet metal geometry and precision machined mounting features. Traceability requirements make single-source manufacturing simpler from a documentation standpoint. Jennison is ISO 9001 certified, which is a baseline requirement for aerospace supply chains.

Defense. ITAR registration adds compliance complexity that multiplies with every additional supplier in the chain. Keeping stamping and machining under one ITAR-registered roof reduces the number of facilities that need to maintain compliance for a given part. Jennison is ITAR registered.

Medical devices. Biocompatible materials, tight tolerances, and stringent quality documentation are standard. When stamped and machined features both need to meet medical device requirements, having one quality system manage both operations simplifies the regulatory burden.

Energy and electronics. Volume requirements favor stamping for base components. Precision machining adds the functional features. The combination delivers the cost efficiency of stamping with the precision of machining where the part actually needs it.

The common thread across all these industries: the more demanding the quality and documentation requirements, the more valuable it is to have both operations under one roof.

How to Get Started With Integrated Stamping and CNC Machining

If your part needs both stamped and machined features, here is what to bring to the conversation with a manufacturing partner.

The full part print. Not just the stamping features or the machining features. The complete print with every dimension, tolerance, and surface finish callout. A single-source manufacturer needs to see the whole picture to plan how both operations will work together.

Material specifications. The material grade, temper, and thickness affect both the stamping process and the machining operations. Some materials stamp easily but are difficult to machine. Others machine well but present forming challenges. Knowing the material upfront lets the engineering team plan both operations together.

Volume requirements. Annual volume and expected lot sizes determine whether stamping is the right approach for the base geometry, or whether CNC machining the entire part from billet might be more cost-effective at lower quantities.

Quality and certification requirements. ISO, ITAR, AS9100, or industry-specific quality standards. Knowing these upfront ensures the manufacturing partner's quality system can support the documentation your industry requires.

Secondary operations. If the part needs plating, heat treating, or other processing after stamping and machining, mention it early. It affects the manufacturing sequence and may influence which operations are done first.

Ready to discuss a part that needs both stamping and CNC machining? Contact Jennison to start the conversation.

Frequently Asked Questions

How do tolerances transfer between stamping and CNC machining operations?

When both operations happen in the same facility, the machining fixtures are designed to reference the actual stamped features, not just theoretical dimensions from the drawing. This means the machined features are positioned relative to where the stamped geometry actually landed, not where it was supposed to land on paper. The result is better alignment between stamped and machined features than what typically occurs when two separate shops fixture the part independently.

Does it cost more to use one shop for both stamping and machining?

In most cases, it costs less. You eliminate shipping between facilities, reduce inspection duplication, and avoid the coordination overhead of managing two suppliers. The per-operation cost at a single facility may be comparable, but the total landed cost of the finished part is typically lower because you remove the hidden costs of split manufacturing: transit, queue time, duplicate quality documentation, and tolerance stacking rework.

What materials work for both stamping and CNC machining?

Most metals commonly used in stamping are also machinable. Carbon steel, stainless steel, aluminum, copper, and brass all stamp and machine well. Some materials present trade-offs: high-strength alloys that are chosen for their mechanical properties may be more difficult to machine, requiring slower feed rates or specialized tooling. Your manufacturing partner can advise on how material selection affects both operations.

How long does a combined stamping and machining project typically take?

Lead time depends on whether new stamping tooling is required. If tooling already exists, production lead times for combined operations are typically comparable to what each operation would take separately, minus the shipping and queue time you would lose in a split-manufacturing setup. For new tooling projects, the die build timeline is the primary driver, with machining setup happening in parallel.

Can any stamping shop also do CNC machining?

Not all stamping shops have CNC machining capability. Some focus exclusively on stamping and outsource machining to partner shops. When evaluating a manufacturer for combined operations, ask specifically about in-house machining equipment, capacity, and the range of work they handle. The depth of machining capability matters. A shop with a single mill is different from one with 18 machining centers running around the clock.

What is the minimum quantity for combined stamping and machining parts?

There is no universal minimum, but stamping becomes most cost-effective at higher volumes because the tooling investment is spread across more parts. For lower quantities, it may be more economical to machine the entire part from solid material. Jennison's in-house tool and die department builds and maintains the stamping dies that produce these base geometries, which means tooling questions and machining questions get answered by the same engineering team. The crossover point depends on part complexity, material cost, and the specific stamping and machining operations required. A good manufacturing partner can help you determine which approach makes sense for your volume.