Last updated on September 2nd, 2026 at 10:55 am
Sheet metal fabrication is the process of cutting, forming, joining, and finishing flat metal sheet to create functional parts and assemblies.
A single custom sheet metal part may move through several manufacturing operations, including laser cutting, CNC punching, press brake forming, hardware insertion, welding, finishing, and assembly.
The manufacturing process depends on factors such as the material, thickness, geometry, tolerances, quantity, finish, and functional requirements of the finished part.
What Is Precision Sheet Metal Fabrication?
Precision sheet metal fabrication focuses on producing custom components where dimensions, features, fit, and repeatability affect how the finished part functions.
Common precision sheet metal parts include:
- Brackets and mounts
- Electronic enclosures and chassis
- Control panels
- Covers and guards
- Frames and structural assemblies
- Equipment housings
- Prototype components
- Low-volume production parts
Unlike manufacturing methods that require dedicated production tooling for every geometry, many precision sheet metal parts can be produced directly from digital CAD data using programmable cutting and forming equipment. This makes sheet metal fabrication particularly useful for prototypes, design iterations, and low-volume production.
How Precision Sheet Metal Fabrication Works
Most custom sheet metal parts begin as flat sheet stock. The required manufacturing operations are then determined by the final geometry and specifications.
A typical part may follow a process such as:
- Cut the flat profile: A laser or CNC punch creates the perimeter, holes, slots, cutouts, and other flat features.
- Form the part: A press brake bends the flat blank into its required three-dimensional shape.
- Add secondary features: Hardware, tapped holes, countersinks, formed features, or other required details may be added.
- Join components: Multi-piece assemblies may require welding, riveting, mechanical fastening, or another joining method.
- Apply finishing: Parts may remain unfinished or receive powder coating, anodizing, plating, chromate conversion coating, silk screening, or another specified finish.
- Inspect and assemble: Required dimensions and features are inspected, and multi-component products may receive final assembly before shipment.
Not every part requires every operation. A simple flat laser-cut component may require only cutting and deburring, while a complex assembly may move through cutting, forming, hardware insertion, welding, finishing, inspection, and assembly.
Tolerancing and GD&T Considerations
For mechanical engineers, the goal is not simply to make every dimension as tight as possible. Tolerances should communicate the dimensional control required for the part to fit and function correctly.
Achievable tolerances depend on the manufacturing process, material, thickness, geometry, number of operations, and how a dimension is established or measured.
What Affects Sheet Metal Accuracy?
| Feature | What Affects Accuracy |
|---|---|
| Flat laser-cut features | Material, thickness, feature size, geometry, and cutting conditions |
| Formed dimensions | Material variation, bend angle, bend radius, flange length, tooling, and springback |
| Hole-to-hole dimensions | Whether features are produced in the flat or established after forming |
| Dimensions across bends | Bend variation, material behavior, and tolerance stack across multiple features |
| Welded assemblies | Fit-up, heat input, weld shrinkage, sequence, and fixturing |
| Finished dimensions | Coating thickness, masking, plating, and other finishing requirements |
Design Tips for Tolerancing Sheet Metal Parts
- Use functional tolerances: Apply tighter tolerances where they control fit, alignment, or performance rather than applying them to every dimension.
- Consider the manufacturing sequence: A dimension between two features created during flat cutting may behave differently from a dimension that crosses one or more bends.
- Identify critical mating features: Hole patterns, mounting surfaces, interfaces, and assembly features should receive the dimensional control necessary for the finished product.
- Account for secondary operations: Welding, hardware insertion, and finishing can affect dimensions after the initial cutting and forming operations are complete.
- Avoid unnecessary precision: Tighter tolerances can require additional manufacturing control, inspection, secondary operations, or rework without improving the function of the part.
GD&T in Sheet Metal Fabrication
Geometric Dimensioning & Tolerancing (GD&T) can be useful for communicating functional relationships that are difficult to define using conventional plus/minus dimensions alone.
Common GD&T controls used on sheet metal parts include:
- Position: Controls the location of holes, slots, and other features relative to defined datums.
- Flatness: Controls the form of a surface when flatness is functionally important.
- Perpendicularity: Can control the orientation of a surface or feature relative to a datum.
- Parallelism: Can control surfaces or features that must maintain a specific orientation to one another.
GD&T should communicate the functional requirements of the design rather than simply make the drawing more restrictive. Thin sheet, formed surfaces, and welded assemblies can behave differently from machined components, so unnecessarily restrictive geometric controls may increase manufacturing and inspection complexity.
Discuss Critical Tolerances Early
When a part contains tight tolerances, critical mating features, or GD&T requirements, reviewing them before production can help identify potential manufacturing challenges.
Approved Sheet Metal can review the design to:
- Evaluate tolerances in relation to the manufacturing process
- Identify dimensions that cross bends or multiple operations
- Flag unnecessarily restrictive requirements that may increase cost or lead time
- Review critical hole patterns and mating features
- Suggest design changes that may improve manufacturability or repeatability
At Approved Sheet Metal, we specialize in precision sheet metal fabrication for prototypes and low-volume production parts and assemblies.
Sheet Metal Design for Manufacturing
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Design parts with the sheet metal fabrication process in mind. Reduce cost and get parts on your desk faster! Learn about the following best practices when designing sheet metal parts:
- Hems & Offsets
- Notches & Tabs
- Corners & Welding
- Uniform Thickness and more!
Common Applications for Precision Sheet Metal Fabrication
Precision sheet metal fabrication is used to produce custom components and assemblies across industries where fit, function, durability, weight, and repeatability matter.
Common applications include:
- Electronic enclosures and chassis: Housings for electronics, controls, power supplies, communications equipment, and other components.
- Brackets and mounts: Custom mounting components for equipment, sensors, electronics, robotics, and mechanical assemblies.
- Control panels: Fabricated panels containing cutouts, mounting holes, hardware, labeling, and other features for switches, displays, and controls.
- Medical equipment components: Covers, brackets, housings, frames, and other fabricated components used within medical equipment.
- Aerospace and defense components: Lightweight brackets, enclosures, panels, mounts, and assemblies manufactured to customer drawings and specifications.
- Robotics and automation components: Guards, brackets, frames, equipment covers, sensor mounts, and other custom components.
- Communications equipment: Enclosures, chassis, racks, brackets, and mounting components for communications and networking systems.
- Renewable energy equipment: Covers, enclosures, brackets, electrical components, and other fabricated parts used in energy systems.
- Prototype products: Custom components and assemblies used to test fit, function, appearance, and manufacturability before production.
Common Materials Used in Precision Sheet Metal Fabrication
Approved Sheet Metal works with a range of sheet metal materials. Material selection should be based on the finished part’s strength, weight, corrosion resistance, formability, conductivity, finish, and operating environment.
| Material | Common Reasons to Choose It |
|---|---|
| 5052-H32 Aluminum | Lightweight, corrosion resistant, and well suited to forming for enclosures, brackets, covers, and other fabricated components |
| 6061-T6 Aluminum | Higher-strength aluminum option for appropriate applications, but generally requires more consideration when forming than 5052-H32 |
| Cold Rolled Steel | Cost-effective, strong, weldable, and commonly used for parts that will receive powder coating or another protective finish |
| Stainless Steel | Corrosion resistance, durability, and performance in exposed or demanding environments |
| Copper | Electrical and thermal conductivity for applications such as busbars, electrical components, and thermal-management parts |
ASM fabricates sheet metal up to approximately 1/4″ thick depending on the material, geometry, and processes required.
Material availability, alloy, temper, thickness, and sheet size can also influence manufacturing cost and lead time.
Our Precision Sheet Metal Fabrication Capabilities
A custom sheet metal part may require several different processes before it is complete. Our fabrication capabilities include:
Laser Cutting
Laser cutting creates the flat profile, holes, slots, cutouts, and other features of a sheet metal part before forming.
Because the cutting path is programmed digitally, laser cutting is particularly useful for prototypes, low-volume production, complex profiles, and designs that may change between revisions without requiring dedicated cutting dies.
Laser-cut part design should still account for material thickness, small features, narrow sections, holes near bends, cutout geometry, and material utilization.
CNC Punching
CNC punching uses a punch-and-die combination to create holes, notches, cutouts, and other features in sheet metal.
One major advantage of punching is the ability to create certain formed features directly in the flat sheet using dedicated tooling. Depending on the part and available tooling, these can include louvers, embossments, knockouts, countersinks, and other formed details.
The best choice between punching and laser cutting depends on the part geometry, required features, material, quantity, and available tooling.
Press Brake Forming
Press brake forming converts a flat sheet metal blank into a three-dimensional part by bending the material between a punch and die.
Successful formed-part design requires more than defining the final CAD geometry. Engineers should also consider:
- Material and thickness
- Bend radius
- Minimum flange length
- Hole and feature proximity to bends
- Bend sequence
- Tool access
- Return flanges and back bends
- Deep-box geometry
- Material springback
A part that can be modeled in CAD is not automatically formable on a press brake. Tooling must be able to reach each bend without colliding with previously formed features.
Hardware Insertion
Hardware insertion adds functional attachment points to sheet metal components using self-clinching nuts, studs, standoffs, Rivnuts, and other hardware.
Self-clinching hardware is installed into a correctly sized mounting hole using controlled squeezing force. The surrounding sheet material flows into the fastener’s retention features to secure it to the panel.
Hardware selection should account for:
- Exact manufacturer and part number
- Thread size
- Mounting-hole diameter
- Sheet thickness
- Sheet material and hardness
- Minimum edge distance
- Installation side
- Finish and masking requirements
Specifying the exact hardware part number on the drawing helps prevent ambiguity during quoting and manufacturing.
Welding
Welding joins fabricated components into permanent sheet metal assemblies.
Approved Sheet Metal uses processes including MIG, TIG, resistance spot welding, seam welding, and plug welding depending on the material, thickness, joint geometry, appearance, and assembly requirements.
Welded assemblies should be designed with joint access, heat input, distortion, fixturing, weld sequence, cosmetic requirements, and post-weld dimensions in mind.
Finishing
Sheet metal parts can be supplied unfinished or with finishing processes such as powder coating, anodizing, plating, chromate conversion coating, silk screening, and other specified finishes.
Finishing should be considered during the design stage because it can affect:
- Finished dimensions
- Hole and slot clearances
- Threads
- Masking requirements
- Grounding and electrical contact surfaces
- Cosmetic surfaces
- Hardware installation sequence
- Lead time
Assembly
Multi-component products can also be assembled after fabrication and finishing.
Depending on the design, assembly may involve welding, rivets, screws, self-clinching hardware, Rivnuts, or a combination of joining methods.
Designing the assembly process early helps ensure that components can be positioned correctly, fastening tools remain accessible, and the selected joining method supports the product’s service and maintenance requirements.
What Determines Sheet Metal Fabrication Cost?
There is no single cost-per-part formula that applies to every custom sheet metal design. Cost is influenced by the material and the complete sequence of manufacturing operations required to produce the part.
Common cost drivers include:
- Material type and thickness
- Material utilization and scrap
- Cutting time and feature complexity
- Number of bends
- Unique forming setups
- Hardware and hardware insertion
- Welding and fixturing
- Grinding or cosmetic weld finishing
- Powder coating, plating, anodizing, or other finishes
- Inspection and documentation requirements
- Assembly requirements
- Order quantity
Design for manufacturability can often reduce cost by simplifying operations without changing the function of the finished part.
What Determines Sheet Metal Fabrication Lead Time?
Lead time depends on both the part design and the manufacturing processes required to complete the order.
Factors that can affect lead time include:
- Material availability
- Part complexity
- Order quantity
- Number of manufacturing operations
- Hardware availability
- Welding and assembly requirements
- Outside finishing processes
- Inspection and documentation requirements
- Current manufacturing capacity
A relatively simple flat laser-cut part may move through production much faster than a multi-component assembly requiring forming, hardware, welding, outside finishing, and detailed inspection.
Prototype and Low-Volume Sheet Metal Fabrication
Modern sheet metal fabrication is particularly well suited to prototypes and low-volume production because many parts can be produced using programmable equipment and standard tooling rather than dedicated stamping dies.
This allows engineers to:
- Produce initial prototypes in low quantities
- Test fit and function before committing to larger quantities
- Revise CAD geometry between orders
- Produce bridge quantities while another manufacturing process is being developed
- Continue using the same general fabrication process for low-volume production
The most efficient manufacturing method can change as quantities increase, so expected production volume should be discussed during quoting.
From CAD Model to Finished Sheet Metal Part
1. RFQ and DFM Review
The process begins with the customer’s CAD files, drawings, quantities, and manufacturing requirements.
Providing both a 3D CAD model and a dimensioned 2D drawing gives the fabricator two different types of information.
The 3D model defines the part geometry, while the drawing communicates requirements such as:
- Material and thickness
- Tolerances
- GD&T
- Finish
- Hardware
- Weld requirements
- Inspection requirements
- Special notes and specifications
Our team can review the design for manufacturability and identify features that may affect fabrication, cost, or lead time. For additional guidance, you can also download our Sheet Metal Design for Manufacturing eBook.
2. Quote and Order
Once the design is ready, submit the project through our digital RFQ with the required files, quantities, and specifications.
Providing complete information up front helps reduce clarification during quoting and gives our estimating team the information needed to evaluate the complete manufacturing process.
3. Programming
After an order enters production, manufacturing data is developed from the customer’s CAD model and drawing requirements for the equipment and operations required to produce the part.
Digital programming reduces manual interpretation and supports repeatable manufacturing, while the drawing remains the source for tolerances, finishes, hardware, inspection requirements, and other specifications not defined by geometry alone.
4. Fabrication
The part then moves through the required manufacturing operations. Depending on the design, these may include laser cutting, punching, forming, hardware insertion, welding, and other secondary processes.
5. Finishing
If a finish is specified, the fabricated parts are prepared for the required process. Masking, cosmetic requirements, grounding surfaces, threads, and other finish-sensitive features should be clearly identified on the drawing.
6. Inspection and Assembly
Parts are inspected according to the drawing, purchase order, and applicable inspection requirements. Multi-component products may then receive final hardware or assembly operations as required.
What to Include in a Sheet Metal Fabrication RFQ
For the most complete quote and DFM review, provide:
- 3D CAD model
- Fully dimensioned 2D drawing
- Material and thickness
- Order quantity
- Finish requirements
- Hardware manufacturer and part numbers
- Weld requirements
- Critical tolerances and GD&T
- Inspection or documentation requirements
- Assembly requirements
- Any applicable specifications or customer-specific requirements
Ready to manufacture your next prototype or low-volume sheet metal project? Request a quote to get started.
Recommended Default Sheet Metal Tolerances
| DIM | Tolerance (MM) | Tolerance (Inches) | Description |
| A | ± 0.13 | ± 0.005 | Sheared Edge to Hole |
| B | ± 0.13 | ± 0.005 | 2 Holes on One Surface |
| C | ± 0.25 | ± 0.010 | Formed Edge to Hole |
| D* | ± 0.76 | ± 0.030 | Holes Across 2 Bends |
| E* | ± 0.76 | ± 0.030 | Holes Across 4 Bends |
| F | ± 0.25 | ± 0.010 | Sheared Edge to Bend |
| G | ± 0.38 | ± 0.015 | Across 2 Bends |
| H* | ± 0.76 | ± 0.030 | Formed Part |
* Dimensions D, E and H are not recommended forms of dimensioning
These tolerances are recommended and best practices. We can obtain tighter tolerances (depending on part geometry/ construction), contact us for more information Download PDF
Metal Fabrication FAQ
What does metal fabrication involve, and what processes does it include?
Metal fabrication encompasses various techniques used to manipulate flat metal into diverse shapes and structures. Processes such as forming, bending, cutting, punching, stamping, shearing, welding, and assembly are fundamental to metal fabrication.
What are the four main categories of metal fabrication?
The categories are Structural Fabrication (focuses on large-scale components for construction), Industrial Fabrication (manufacturing for industrial applications), Commercial Fabrication (crafting for commercial enterprises), and Precision Metal Fabrication (highly accurate parts).
What are some common applications for precision sheet metal fabrication?
recision sheet metal fabrication finds applications in electronics enclosures, aerospace components, automotive parts, medical equipment, HVAC systems, appliance manufacturing, consumer electronics, architectural metalwork, and more.
Which types of metals are commonly used in precision metal fabrication?
Fabricators often work with aluminum, cold-rolled steel, copper, and stainless steel, utilizing sheets up to ¼ inch thick to create precise components.
What are some key processes involved in precision metal fabrication?
The critical operations include laser cutting (for precise designs), punching (creating holes and intricate shapes), forming (reshaping metal), hardware insertion (enhancing functionality), welding (creating strong bonds), and finishing (powder coating, silk screening, plating, etc.).
How does your metal fabrication process ensure precision and quality?
The process begins with design optimization for manufacturability, followed by efficient quoting and order placement. Automation, CAD software, and state-of-the-art machinery are employed to program and execute the fabrication process accurately, ensuring minimal errors and precise outcomes.
What is involved in the finishing and assembly stages of metal fabrication?
Finishing includes services like powder coating, silk screening, plating, and more, enhancing aesthetics and durability. Assembly services involve complete manufacturing workflows, including joining methods like welding or fastening.