Q&A

PECM FUNDAMENTALS

What is PECM, and how does it differ from conventional ECM?

PECM (Pulsed Electrochemical Machining) is an advanced form of ECM that uses pulsed current and tighter control of the tool-to-part gap. It enables finer features, tighter tolerances, and smoother surface finishes compared to conventional ECM.

PECM builds on traditional ECM by adding pulse-controlled electrical current, micron-scale gap control, and more refined electrolyte flow. While conventional ECM uses a constant current to remove material through anodic dissolution, PECM uses rapid electrical pulses to more precisely shape hard metals without heat, stress, or tool wear. PECM is better suited for high-precision parts (like those found in medical, aerospace, or energy applications) where surface finish, burr-free geometry, and repeatability are critical. Compared to ECM, PECM achieves tighter tolerances and smoother surfaces.

What problems does PECM solve that other processes can't?

PECM solves machining challenges like burrs, heat damage, and tool wear on complex metal parts--ideal for finishing fragile, intricate, or heat-sensitive geometries that traditional methods can’t handle cleanly.

PECM is uniquely effective for non-contact, high-precision finishing where other processes fall short. It can machine tight internal channels, burr-prone features, superalloys, and delicate lattices without inducing heat, mechanical stress, or recast layers. EDM, laser, and grinding processes often leave burrs, microcracks, or HAZ, especially on hard or reactive metals. PECM avoids these entirely by dissolving metal atom by atom, rather than melting or cutting it. It’s especially valuable for industries like medical, aerospace, and AM, where part integrity, surface quality, and repeatability are critical.

In simple terms, how does PECM work?

PECM removes metal by sending pulsed electrical current through an electrolyte between a shaped tool and a metal part. The tool never touches the part—material is dissolved away with no heat or force.

PECM works by using electricity to dissolve metal in a controlled way. A custom-shaped tool (called a cathode) is placed very close to the metal part (the anode) inside an electrolyte bath. Then, pulsed electrical current is applied. This causes metal atoms on the part’s surface to ionize and dissolve into the fluid, matching the shape of the tool without ever making contact. Because there's no heat, no friction, and no tool wear, PECM can deliver burr-free, stress-free results even on delicate or heat-sensitive materials like titanium or Nitinol. The result is a highly accurate, scalable process ideal for intricate components in industries like medical devices, aerospace, and energy.

When shouldn't I use PECM?

PECM is unsuited for low-volume parts, non-conductive materials, or extremely large, simple geometries where tooling costs outweigh the benefits.

PECM only works on electrically conductive materials, so plastics, ceramics, and most composites are off-limits. It also requires custom cathode tooling and process development, which adds cost and lead time, making PECM less economical for one-off prototypes or simple parts that could be milled or polished faster. Additionally, PECM is best for small to medium-sized features; machining extremely large flat surfaces may not justify the setup investment. In general, PECM shines in repeatable, high-precision production, not quick-turn manual jobs.

Is PECM a subtractive or additive process?

PECM is an inherently subtractive manufacturing process, removing material from a metal part via electrochemical dissolution.

PECM works by removing material from a conductive metal part using electrochemical reactions, specifically anodic dissolution. There is no melting, cutting, or deposition. Instead, metal ions are selectively dissolved from the surface wherever current flows between the tool and part through the electrolyte. This makes PECM well-suited for final surface shaping, finishing, or internal feature formation on metallic parts that are hard to machine mechanically. It’s particularly effective for refining parts that have already been formed by casting, forging, or additive manufacturing--giving them precise, burr-free finishes without changing the base material properties.

What is "minimal tool wear" and why does it matter?

In PECM, the cathode tool doesn’t touch the part, dramatically reducing (but not fully eliminating) the rate of tool wear.

Unlike traditional machining, where cutting tools degrade from friction and force, PECM is completely non-contact. The cathode (tool) is separated from the workpiece by a narrow electrolyte gap, and material is removed via controlled electrochemical reactions. Because the tool never touches the part, there's no abrasion, no thermal damage, and no dimensional drift from tool wear. This matters most in high-volume production, where feature-to-feature consistency and tight tolerances must be maintained over thousands (or tens of thousands) of parts. "Minimal tool wear" means less downtime, more predictable quality, and a lower cost of ownership over time.

Capabilities, Specs & Quality

What surface finish can PECM achieve on different materials?

PECM typically achieves 4–12 µin Ra surface finishes, but results depend more on geometry and material removal depth than on material type alone.

While PECM is compatible with a wide range of conductive metals (like titanium, Nitinol, Inconel, stainless steel, and copper alloys) the resulting surface finish depends more on the geometry of the part and the amount of material being removed than on the specific alloy. In general, PECM can deliver sub-micrometer-Ra finishes on most materials. Shallow removal passes over well-designed cathode geometries yield smoother results, while deeper or more aggressive removal may require post-polishing to meet tighter specs. Unlike grinding or polishing, PECM maintains consistent finish on complex 3D shapes, internal channels, and lattice structures with no tool marks, no burrs, and no heat-affected zones.

What's the smallest feature size/wall thickness PECM can produce?

PECM can produce wall thicknesses under 0.075 mm depending on geometry, material, and process control. However, results depend on cathode design and electrolyte flow.

PECM is well-suited for creating very fine features and thin walls, thanks to its non-contact, burr-free nature. In Voxel’s experience, wall thicknesses under 0.075 mm (75 microns) are achievable in controlled geometries, especially where electrolyte flow and current density can be evenly managed. Achievable feature size is influenced by tool shape, voltage waveform, and part design, and not every geometry supports ultra-thin features reliably. That said, PECM is uniquely capable of delivering delicate features without mechanical stress or tool deflection, making it a compelling option for stents, spinal cages, microfluidics, and thin-lattice structures.

What tolerances are typical with PECM? How repeatable are they?

PECM can achieve tight tolerances and high repeatability, but results depend heavily on part geometry, feature size, and material removal depth.

PECM is capable of producing high-precision features, but achievable tolerances depend on several factors. In particular the geometry of the part, the complexity of the features, and how much material is being removed. In general, the process is highly consistent and repeatable because there’s no tool wear or heat distortion, which often degrade accuracy in conventional machining. While tight tolerances are possible, Voxel typically works with customers to validate performance through sampling and data, rather than promising fixed tolerance bands up front. The best results are seen in geometries that allow stable cathode design, uniform electrolyte flow, and controlled material removal over small cross sections.

How is PECM capable of handling burr-free machining?

PECM's lack of heat or contact makes it inherently burr-free. Electrochemistry does not create mechanical deformation.

PECM produces burr-free features by design. Because the process removes material through anodic dissolution, there's no cutting edge, shear force, or mechanical deflection that would leave behind burrs or chips. The shaped cathode defines the removal zone, and the electrolyte carries dissolved ions away cleanly. This makes PECM ideal for finishing complex contours, micro slots, and internal passages where burrs would be difficult to detect or remove. Eliminating burrs also improves assembly fit, part cleanliness, and downstream inspection efficiency, especially in regulated applications like medical implants or aerospace seals.

Is PECM capable of machining internal features reliably?

Yes. PECM is uniquely capable of machining and finishing internal channels and cavities, especially in metals that are hard to cut mechanically.

PECM is a powerful option for internal feature machining, especially for parts produced via additive manufacturing, or designs involving cooling channels, blind cavities, or complex internal contours. Since the process uses a shaped cathode and pulsed electrical current rather than contact or cutting, PECM can reach and uniformly finish features that are otherwise inaccessible. Internal geometries that would be difficult or impossible to polish, deburr, or EDM can often be PECM-processed with consistent cross-sectional accuracy and no burrs. It’s particularly valuable for aerospace combustors, medical implants, or thermal management components with high aspect ratio features or delicate internal forms.

Does PECM create recast layers, HAZ, residual stress, or microcracks?

No. PECM is a non-thermal, non-contact process that leaves no recast layer, no heat-affected zone (HAZ), and no microcracks in the material.

Unlike EDM or laser machining, PECM is an electrochemical process that generates no thermal energy at the cutting interface. Since there’s no spark, arc, or friction, there is no recast layer, no microstructural phase change, and no risk of heat-induced microcracks. Material is removed atom by atom via a controlled anodic reaction in an electrolyte environment. This makes PECM especially attractive for sensitive alloys like titanium, Inconel, and Nitinol, where surface integrity and fatigue strength are critical. The result is a clean, consistent surface that’s ready for coating, inspection, or end use—no stress relief or secondary processing required.

MATERIALS

What materials are best-suited for PECM? Which are not?

PECM only works on electrically conductive metals, including hard-to-machine alloys like titanium, Nitinol, Inconel, stainless steel, and cobalt-chrome.

PECM is compatible with any electrically conductive metal, but it’s especially advantageous for tough, corrosion-resistant, or heat-sensitive alloys. These include Ti64 (Ti-6Al-4V), Nitinol, Inconel, cobalt-chrome, stainless steels (300/400 series), and copper alloys. Because PECM removes material without heat or mechanical force, it’s often preferred for materials that are difficult to cut, grind, or EDM due to burr formation, tool wear, or microstructural damage. The process also performs well on biocompatible metals commonly used in medical devices and implants. Material conductivity, reactivity with electrolyte, and dimensional goals all ultimately factor into PECM suitability.

Can PECM process additively manufactured parts?

Yes. PECM is highly effective at finishing metal additive parts, especially for removing downskin roughness, supports, and burrs from internal channels or lattices.

PECM is sometimes utilized as a postprocessing method for metal additive components. It’s particularly effective at removing support artifacts, powder-sintered roughness, and downskin texture on metals like titanium and Inconel. Because PECM is non-contact, it can access and finish internal channels, cavities, and complex lattice structures without damaging surrounding geometry. This makes it ideal for heat exchangers, orthopedic implants, fuel cell plates, and other AM parts where internal surfaces need high-quality finishes for fluid flow, fatigue life, or biocompatibility. The ability to selectively remove material without recast or distortion makes PECM a strong match for AM complexity.

How does PECM behave on hard, tough, or heat-resistant materials?

PECM performs exceptionally well on most hard and heat-resistant alloys, including some refractory metals.

PECM is often chosen specifically because it performs independently of material hardness. Alloys that are difficult or expensive to machine via EDM, grinding, or laser—like Inconel, titanium, cobalt-chrome, and refractory metals—are good candidates. PECM is unaffected by the toughness or melting point of the material, allowing for precise, burr-free machining of exotic alloys without the risk of microcracks, heat-affected zones, or tool breakage.

Tooling, Electrolytes, Process Control

What is the role of the cathode, or "tool" in PECM?

In PECM, the cathode is a custom-shaped tool (usually the inverse of the desired geometry of the part) machining the part without contact.

In PECM, the cathode is custom-shaped as the inverse of the desired geometry of the workpiece. During machining, it's placed extremely close to the workpiece (the anode) with a precise electrolyte gap in between. When pulsed current flows, the cathode channels the current field to remove metal from the part only where needed, allowing for complex contours and tight tolerances. Since there’s no contact, the cathode doesn’t wear down like a traditional cutting tool.

How is the electrolyte chosen, managed, and disposed of?

The electrolytic fluid is selected based on the material and process, and is filtered, monitored, and reused during production.

Typically made of salt-based aqueous solutions (like sodium nitrate or sodium chloride), the electrolyte supports ion exchange between cathode and workpiece. The specific chemistry is tailored to the part material and machining goals to control removal rate, surface finish, and tool life. During production, the electrolyte is continuously filtered and recirculated to remove metal ions and maintain chemical stability. Over time, it becomes saturated and must be reconditioned or responsibly disposed of, in accordance with environmental safety standards.

Which process parameters affect the accuracy of PECM the most?

PECM's accuracy is influenced by voltage pulse shape, tool-to-part gap, electrolyte flow, cathode geometry, and many other factors.

Several parameters govern how precisely PECM removes material. Key factors include, but are not limited to, pulse voltage, pulse rate, inter-electrode gap, electrolyte flow, electrolyte temperature, cathode design, and many more. Tuning these parameters correctly allows PECM to maintain tight tolerances and smooth finishes across complex parts.

Throughput, Cycle Time, Scaling

How fast is PECM compared to competing processes? What affects that?

PECM can offer competitive cycle times, but actual speed depends on geometry, feature size, and material removal depth, not just the material itself.

PECM isn’t defined by spindle speed or cutting feed; it removes material through controlled electrochemical reactions. That means cycle time is a function of material removal volume, cathode design, and current density, not just toolpath efficiency. For some geometries, PECM can be faster than EDM, polishing, or abrasive finishing--especially when factoring in burr removal and surface cleanup. In other cases, particularly deep or heavy stock removal, PECM may take longer. The process is best judged on its net productivity: if it eliminates multiple downstream steps (deburring, inspection, polishing), PECM may yield shorter overall lead times, even if material removal per second isn’t faster.

How can PECM be parallelized for high volumes?

PECM can be scaled using multi-part tooling, allowing dozens of identical parts or features to be machined simultaneously.

PECM accomplishes high feature-to-feature and part-to-part repeatability through multi-part fixturing, multi-feature cathodes, and cell-based production setups. Because the process is non-contact and tool wear is minimal, there's little variation introduced across parallel parts, making PECM well-suited for high-volume, parallel-processed manufacturing.

What factors primarily affect the cycle times in PECM?

Cycle time in PECM is driven by material removal depth, feature complexity, cathode size, and electrolyte management.

Key drivers of PECM cycle time include, but are not limited to, material removal volume, feature complexity, cathode surface area, and electrolyte temperature/flow.

Voxel optimizes each process around a target removal rate, balancing tolerance, surface finish, and speed and often consolidates multiple steps (e.g., deburring + polishing) into a single PECM cycle.

Costs & ROI

How much does PECM cost per-part compared to other processes?

PECM's costs depends on geometry, material, removal depth, and especially volume. It often replaces multiple finishing steps, which can lower total cost at scale.

There’s no fixed “per-part” price for PECM—cost is shaped by several factors, including the amount of material veing removed, feature complexity, part size, surface area, and tooling requirements. However, production volume is likely the most critical factor.

PECM can be highly cost-effective in mid- to high-volume production, especially when it replaces multiple downstream processes like deburring, grinding, polishing, or inspection rework. Voxel typically evaluates parts on a case-by-case basis to develop an optimized process and provide accurate cost models. If you’re exploring PECM for a specific part, uploading a STEP file is the best way to get started.

How do tooling costs and NRE amortize across volumes?

PECM involves upfront tooling and process development (NRE), but these costs are amortized over production volume, allowing per-part cost to drop significantly at scale.

Due to custom tooling, there is always non-recurring engineering (NRE) costs associated with launching a new part. These include cathode design, electrolyte optimization, fixture development, process validation and more. Fortunately, as PECM tooling can be reused across thousands of parts without performance loss. As a result, the upfront investment becomes more cost-effective as volume increases. Voxel works closely with customers to estimate break-even volumes and plan scalable programs that balance performance, cost, and lead time.

What is the cost of purchasing PECM equipment?

Voxel generally doesn’t sell PECM equipment directly. We offer PECM as a scalable service with custom tooling, process development, and production capability.

Voxel operates as a precision manufacturing partner, as is generally not not a machine vendor. Most turnkey ECM machines are sold through niche OEMs and require substantial investment in tooling, electrolyte chemistry, controls integration, and safety infrastructure. For most customers, it’s faster and more cost-effective to partner with a PECM service provider like Voxel rather than purchasing equipment outright.

If your team is considering building PECM capability internally, we’re happy to advise on feasibility, readiness, and process risks.

Comparing PECM and...

Compare PECM and electrical discharge machining (EDM)?

PECM is a non-contact, non-thermal process that removes metal via electrochemistry. EDM uses sparks to erode metal and can leave burrs, recast layers, and microcracks.

PECM is often chosen when surface integrity, consistency, and feature repeatability are critical—especially for medical implants, aerospace parts, and heat-sensitive alloys. EDM may be better suited for sharp corners or small-volume machining when a hard toolpath is needed and some surface artifacts are acceptable. See our article on this topic.

Compare PECM and conventional lapping/grinding/honing?

Unlike conventional processes like grinding, lapping or honing, PECM machines with a single, burr-free, stress-free pass that conforms to complex geometries.

Conventional finishing methods like grinding, lapping, and honing are mechanical processes that inherently require contact between the tool and workpiece and rely on friction for material removal. While lapping or honing may deliver slightly finer Ra values on simple flat surfaces, PECM excels when those surfaces are curved, hidden, internal, or fragile, and it’s especially valuable when trying to eliminate multiple manual finishing operations. See our article on this topic.

Compare PECM and photochemical etching (PCE)?

PECM offers greater dimensional control and repeatability than chemical etching, with no undercutting, isotropic removal, and tighter tolerances.

Chemical etching (also called photochemical machining) uses acids and masking layers to selectively dissolve metal. It’s effective for 2D features on thin sheets, but it has several limitations-- as it tends to produce undercuts and unpredictable taper, and is generally limited to thin cross-sections. While chemical etching is cheaper for flat parts or photo-defined masks, PECM is far more capable for functional geometry, internal features, and precision 3D components. See our article on this topic.

PECM & Medical Devices

What medical devices has PECM been used to produce?

PECM has been used to manufacture or finish orthopedic implants, including nitinol bone fixtures, cardiovascular devices, and surgical end effectors.

PECM is a proven solution for high-precision components in regulated medical markets. Applications include orthopedic devices such as nitinol bone fixtures, cardiovascular implants, and surgical end-effectors. Because PECM is non-contact and burr-free, it allows medical device companies to achieve geometries that are difficult to polish mechanically, while also reducing risk of debris, microcracks, or thermal damage--all of which are critical in FDA-regulated environments.

How does PECM benefit medical device manufacturing?

PECM enables burr-free, biocompatible surfaces on complex metal parts, improving safety, regulatory compliance, and downstream assembly in medical devices.

PECM's benefits to medical device manufacturing include, but are not limited to, its ability to produce burr-free, superfinished surfaces that preserve surface integrity and improve sterility, processing challenging medical materials like nitinol and cobalt-chrome, and scale complex features to high volumes to meet growing demand.

What role can PECM play for microfluidic features, IE drug delivery, etc?

PECM can precisely machine and finish microfluidic channels, ports, and nozzles in metal drug-delivery systems without clogging, burrs, or heat damage.

In drug delivery and microfluidic systems, PECM can be used to create clean, burr-free internal features that are difficult or impossible to reach with mechanical tools, including injection ports, metered nozzles, or micro-channels. Because PECM leaves no burrs, no edge deformation, and no heat-affected zone, it supports predictable fluid dynamics and eliminates common risks like particle shedding or dimensional drift. It’s especially useful for devices where metal miniaturization intersects with regulatory safety standards.

PECM & Aerospace

What aerospace components has PECM been used to produce?

PECM has been used to machine or finish turbine blades, blisks, stator vanes, heat exchangers and more for aerospace leaders.

In aerospace and propulsion systems, PECM is leveraged to produce components with tight feature control and high-temperature material requirements. Common applications include turbine blades and blisks, stator vanes and internal airfoil channels, and microchannel heat exchangers. PECM is especially useful for nickel-based superalloys and complex contours that are hard to grind or EDM reliably. Its ability to preserve surface integrity while enabling tight feature-to-feature variation makes it a strong fit for flight-critical parts.

How do critical aerospace components benefit from PECM?

PECM improves dimensional control, fatigue life, and surface quality with no burrs, recast layers, or microcracks in critical aerospace components.

Critical aerospace components often require flawless surface integrity and consistent geometry under extreme thermal and mechanical loads. PECM supports this by eliminating burrs/microcracks/recast layers, preserving the base microstructure of alloys, and removing material without inducing residual stress or tool deflection. Because PECM is non-contact and isothermal, it allows high-strength metals to be machined without compromising their fatigue behavior. It's also highly repeatable, making it suitable for feature-rich, performance-critical components where part-to-part variation must be tightly controlled, such as turbine hardware or thermal management systems.

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