Trepanning is a process used to create a hole in a workpiece by machining only the outer area of the hole, leaving an unmachined core in the center. A BTA drill creates the same hole by turning all of the material into chips, leaving no core behind. This gives manufacturers two distinct ways to create a hole from solid material.
18

Nov

WHEN IS TREPANNING THE RIGHT CHOICE?

oil field manufacturing application example

Trepanning is a process that creates a hole in a workpiece by machining only the outer area of the hole, leaving an unmachined core in the center. In contrast, a BTA drill creates the same hole by turning all of the material into chips, leaving no core behind. This provides manufacturers with two distinct ways to create a hole from solid material.

BTA drilling is simple in concept: set up the machine, drill the hole, remove the workpiece, and empty the chip hopper when it’s full. Many manufacturers choose this process for its straightforward operation and the convenience of chip recycling. Trepanning isn’t necessarily more difficult, but it requires more operator involvement. When the hole is complete, the retained core must be removed from the tool between cycles.

Trepanning and BTA solid drilling share the same coolant delivery and chip evacuation systems. Coolant is introduced around the outside of the tool, and chips are exhausted through the drill tube. In BTA drilling, coolant passes freely through the tube, carrying chips to the conveyor. In trepanning, however, chips taken by the coolant must pass by the workpiece core inside the tube. The bore quality between the two methods can be similar, but it depends on the tool design. Trepanning tools with a sufficient cutting width to engage guide pads can achieve diameter tolerances similar to solid drilling. Tools designed for the narrowest width of cut (leaving the largest core) generally produce lower bore quality. For very deep holes, a counter-rotating tool and workpiece are often used. Because the trepanning core rotates with the workpiece, it can create challenges related to vibration or unexpected loading. Once these differences are understood, the key question becomes: When is trepanning the right choice?

ADVANTAGES OF TREPANNING

Saving the Core: One of the most significant advantages of trepanning is the ability to retain the core. The core may hold value for quality inspection or certification of critical parts. Because it originates from the same piece of raw material as the finished component, metallurgical samples can be documented or kept as a coupon for future evaluation if a finished part fails. In some cases, the core can be repurposed as a smaller workpiece, offering an economic advantage. Depending on size and material, the scrap value of the core may even exceed that of chips created through solid drilling.

Less Power for Machining (Sometimes): When the center of the workpiece isn’t machined away, machining forces can be reduced compared to solid drilling. This advantage is most evident when the tool is cutting a narrow width relative to the hole size and the depth isn’t great enough for the core to bend or rub inside the drill tube, which would otherwise create friction and require more power.

Better Economics in Tooling: Since trepanning does not machine the hole center, a center carbide insert isn’t required, and in some cases, the intermediate insert can also be eliminated. This can lead to significant tooling cost savings in production environments.

ADVANTAGES OF TREPANNING

Saving the Core: One of the most significant advantages of trepanning is the ability to retain the core. The core may hold value for quality inspection or certification of critical parts. Because it originates from the same piece of raw material as the finished component, metallurgical samples can be documented or kept as a coupon for future evaluation if a finished part fails. In some cases, the core can be repurposed as a smaller workpiece, offering an economic advantage. Depending on size and material, the scrap value of the core may even exceed that of chips created through solid drilling.

Less Power for Machining (Sometimes): When the center of the workpiece isn’t machined away, machining forces can be reduced compared to solid drilling.This advantage is most evident when the tool is cutting a narrow width relative to the hole size and the depth isn’t great enough for the core to bend or rub inside the drill tube, which would otherwise create friction and require more power.

Better Economics in Tooling: Because trepanning does not machine the hole center, a center carbide insert isn’t required, and in some cases, the intermediate insert can also be eliminated. This can lead to significant tooling cost savings in production environments.

“Trepanning is not just an alternative to BTA drilling—it’s a strategic choice when core recovery, power efficiency, or tooling economy align with production goals.”

trepanning machine application for oil field

LIMITATIONS AND CONSIDERATIONS

Core Management: Managing and removing the core can be challenging, especially in long workpieces. The end face of the core typically has a sharp, blade-like edge from the final cut. Operators should be properly trained and handle the cores carefully to avoid injury, and the cores must be safely managed as they move through the plant after drilling. The tool head can also be damaged during core removal. Carbide inserts and cartridges should be inspected after each cycle to ensure they are ready for the next workpiece.

Cutting Insert Changes During the Cut: If a cutting insert dulls during trepanning, it’s difficult to index the insert mid-cycle. The tool must be retracted, often with the core still in contact with the inserts that were cutting it. In contrast, a solid-drilled hole allows the tool to be backed out, inserts replaced, and drilling resumed more easily.

Blind Holes: When a hole extends completely through the part, trepanning is straightforward to implement. When a hole is blind—only partially into the workpiece—the core remains attached at the bottom. Special core-breaking strategies or core-cropping tools can separate the core, but these add process complexity.

Chip Clearance Between Core and Drill Tube: The trepanning process leaves a core in the center of the drill tube while producing the hole, which has to compete for space with the chips exiting through the tool. Chip control is crucial, as is managing the wall thickness of the drill tube to ensure compatibility with the trepanning head, targeted hole size, and cutting width.

EQUIPMENT FOR TREPANNING

Many older trepanning machines were designed around lower power requirements and may not be suitable for modern BTA solid drilling. Likewise, trepanning tools designed for high penetration rates or small cores can stress older machines not built for that level of performance. UNISIG B-Series machines are designed to support both trepanning and BTA solid drilling. This gives manufacturers flexibility to choose the process that best fits their production goals—whether prioritizing material recovery, process efficiency, or overall machine utilization.

LIMITATIONS AND CONSIDERATIONS

trepanning machine application for oil field

Core Management: Managing and removing the core can be challenging, especially in long workpieces. The end face of the core typically has a sharp, blade-like edge from the final cut. Operators should be properly trained and handle the cores carefully to avoid injury, and the cores must be safely managed as they move through the plant after drilling. The tool head can also be damaged during core removal. Carbide inserts and cartridges should be inspected after each cycle to ensure readiness for the next workpiece.

Cutting Insert Changes During the Cut: If a cutting insert dulls during trepanning, it’s difficult to index the insert mid-cycle. The tool must be retracted, often with the core still in contact with the inserts that were cutting it. In contrast, a solid-drilled hole allows the tool to be backed out, inserts replaced, and drilling resumed more easily.

Blind Holes: When a hole goes all the way through the part, trepanning is straightforward to implement. When a hole is blind—only partially into the workpiece—the core remains attached at the bottom. Special core-breaking strategies or core-cropping tools can separate the core, but these add process complexity.

Chip Clearance Between Core and Drill Tube: The trepanning process will leave a core in the center of the drill tube while producing the hole, which has to compete for space with the chips exiting through the tool. Chip control is very important, as is managing the wall thickness of the drill tube to be compatible with the trepanning head, targeted hole size, and cutting width.

EQUIPMENT FOR TREPANNING

Many older trepanning machines were designed around lower power requirements and may not be suitable for modern BTA solid drilling. Likewise, trepanning tools designed for high penetration rates or small cores can stress older machines not built for that level of performance. UNISIG B-Series machines are designed to support both trepanning and BTA solid drilling. This gives manufacturers flexibility to choose the process that best fits their production goals—whether prioritizing material recovery, process efficiency, or overall machine utilization.

FREQUENTLY ASKED QUESTIONS

Trepanning is ideal when core recovery or reduced tooling cost is valuable, or when material properties must be preserved for testing or reuse.

It’s possible, but challenging. Specialized core-breaking or cropping tools are required to separate the core, which adds time and complexity.

Machines must be powerful, and designed for core handling. UNISIG B-Series machines can perform both trepanning and BTA drilling, offering flexibility for different applications.

Every company that builds advanced technology products is chasing engineering innovation, looking for clever and practical designs that separate them from the competition. Precision machine tools and automation have evolved to incredible levels because of constant competitive pressure, but that same pressure can leave design engineers searching for fresh inspiration.
05

Nov

MANUFACTURING INNOVATION DRIVES ENGINEERING INNOVATION

Entrust Okuma lights out machining w logo

Every company that builds advanced technology products is chasing engineering innovation, looking for clever and practical designs that separate them from the competition. Precision machine tools and automation have evolved to incredible levels because of constant competitive pressure, but that same pressure can leave design engineers searching for fresh inspiration.

Where does true design innovation come from? While inspiration can occasionally strike out of nowhere, relying on those rare moments is not a sustainable strategy when your profession demands a consistent output of high-quality designs. One of the most reliable and enduring sources of engineering innovation comes from a strong, ongoing connection to manufacturing.

INNOVATION MEETS REALITY

Physics is the ultimate equalizer, and bad ideas rarely survive contact with it. When components are difficult to manufacture, costs rise, quality falls, and reliability suffers. Engineers who stay closely involved with manufacturing learn lessons that sharpen their instincts and shape their decisions. These lessons form the foundation of great engineering work.

Even more exciting, manufacturing technology continuously expands what is possible. Staying connected to those advancements gives engineers a steady stream of inspiration and practical ideas.

INNOVATION MEETS REALITY

Physics is the ultimate equalizer, and bad ideas rarely survive contact with it. When components are difficult to manufacture, costs rise, quality falls, and reliability suffers. Engineers who stay closely involved with manufacturing learn lessons that sharpen their instincts and shape their decisions. These lessons form the foundation of great engineering work.

Even more exciting, manufacturing technology continuously expands what is possible. Staying connected to those advancements gives engineers a steady stream of inspiration and practical ideas.

“We have an endless source of engineering innovation that comes directly from innovations in manufacturing.”

MANUFACTURING EXPANDS POSSIBILITIES

Every improvement in manufacturing capability unlocks new options for engineering design.

  • A modular fixturing system might enable engineers to design parts with more features machined in a single setup, improving accuracy, reducing part counts, and simplifying final machine alignment.
  • A large machine with five-sided machining capabilities can inspire designs that minimize disassembly for faster installation at a customer site.
  • Micron accuracy cylindrical and contour grinding make higher speeds and greater precision attainable.

If you are not regularly talking to the machinists who make these technologies work, you are missing opportunities for innovation.

KEEPING ENGINEERING AND MANUFACTURING TOGETHER

The best companies do not leave collaboration to chance; they build it into their operations. Encouraging, or even requiring, ongoing engagement between design engineering and manufacturing ensures that both teams grow together. This collaboration works best when both are under the same roof.

At UNISIG, we live this philosophy. A management directive mandates that we build our critical components in-house. We invest in machinery, technology, people, and training to remain at the leading edge of manufacturing, not just in assembly. Because our engineers and manufacturing professionals work side by side, we maintain complete control of production and gain a constant flow of new ideas from the shop floor to the design desk.

MANUFACTURING EXPANDS POSSIBILITIES

Every improvement in manufacturing capability unlocks new options for engineering design.

  • A modular fixturing system might enable engineers to design parts with more features machined in a single setup, improving accuracy, reducing part counts, and simplifying final machine alignment.
  • A large machine with five-sided machining capabilities can inspire designs that minimize disassembly for faster installation at a customer site.
  • Micron accuracy cylindrical and contour grinding make higher speeds and greater precision attainable.

If you are not regularly talking to the machinists who make these technologies work, you are missing opportunities for innovation.

KEEPING ENGINEERING AND MANUFACTURING TOGETHER

The best companies do not leave collaboration to chance; they build it into their operations. Encouraging, or even requiring, ongoing engagement between design engineering and manufacturing ensures that both teams grow together. This collaboration works best when both are under the same roof.

At UNISIG, we live this philosophy. A management directive mandates that we build our critical components in-house. We invest in machinery, technology, people, and training to remain at the leading edge of manufacturing, not just in assembly. Because our engineers and manufacturing professionals work side by side, we maintain complete control of production and gain a constant flow of new ideas from the shop floor to the design desk.

FREQUENTLY ASKED QUESTIONS

Manufacturing advancements expand what is physically possible to build. When engineers stay connected to the shop floor, they gain real-world insights about materials, processes, and tolerances that influence smarter, more efficient designs.

Close collaboration ensures that designs are practical, efficient to produce, and optimized for quality and performance. When both teams operate in the same facility, feedback flows naturally, leading to faster innovation and fewer design challenges.

UNISIG builds its critical components in-house, investing in advanced machinery, technology, and training. By keeping manufacturing and engineering under one roof, the company maintains full control over production and continuously drives innovation in both areas.

Automation is part of our DNA at UNISIG. Many of our deep hole drilling machine projects include some level of automation, and we think about it at every step of development. This approach allows us to offer customers automation options with their initial purchase or as a future upgrade, ensuring their investment is compatible with automated production.
04

Nov

WHAT DOES IT MEAN TO BUILD AUTOMATION?

Automation Gundrilling Cell

Automation is part of our DNA at UNISIG. Many of our deep hole drilling machine projects include some level of automation, and we think about it at every step of development. This approach allows us to offer customers automation options with their initial purchase or as a future upgrade, ensuring their investment is compatible with automated production.

UNISIG machines are servo-driven and equipped with programmable feed rates, positions, and spindle speeds that optimize production. Many models also include servo-driven workpiece positioning systems that automatically prepare the machine for the next part. The user interface clearly shows the machine’s position and cycle status, making it simple for operators to complete one cycle and start the next.

Before automating a machine, the drilling operation itself must be stable and controlled. UNISIG’s process monitoring system tracks drilling conditions in real time and can automatically adjust parameters to maintain cycle performance. When limits are reached, the machine interrupts operation to protect the tool and workpiece while communicating what fault caused the stoppage. This feedback helps operators fine-tune parameters for successful drilling and establish tool life settings for high-volume production.

INTEGRATED AUTOMATION: BUILT FOR EFFICIENCY

Not every automated system requires a robot moving parts around. In-machine automation, such as smart conveyors, indexing pallets, and bulk feeders, can provide fully automated operation within a compact footprint. These integrated systems are often designed to ship with the machine as a single unit, ready for production.

UNISIG also offers “robot-ready” machines. Depending on the model, this can include communication protocols, automatic doors, powered fixturing, and presence sensors. These features simplify future robot integration while making manual operation more efficient for the operator.

“Automation is never an afterthought. It is built in from the very beginning.”

INTEGRATED AUTOMATION: BUILT FOR EFFICIENCY

Not every automated system requires a robot moving parts around. In-machine automation, such as smart conveyors, indexing pallets, and bulk feeders, can provide fully automated operation within a compact footprint. These integrated systems are often designed to ship with the machine as a single unit, ready for production.

UNISIG also offers “robot-ready” machines. Depending on the model, this can include communication protocols, automatic doors, powered fixturing, and presence sensors. These features simplify future robot integration while making manual operation more efficient for the operator.

“Automation is never an afterthought. It is built in from the very beginning.”

READY-ENGINEERED SYSTEMS: PROVEN AND SCALABLE

Standardized automation solutions make it easy for customers to say yes to automation, even without prior experience. UNISIG’s pre-engineered, proven automation eliminates unnecessary risk and development cost. We ask the right questions to help customers avoid common pitfalls and deliver automation systems that enhance productivity and competitiveness.

When multiple machines are connected in an automated system, centralized control simplifies operation and setup. The UNISIG Automation Cell Controller (ACC) provides a single interface that displays operation screens from every UNISIG machine in the cell, along with the robot sequence and parameters for the next job change.

ADVANCED EXPERTISE: SIMPLE UPGRADES TO COMPLEX CELLS

UNISIG has decades of experience designing and integrating automation, from ultra-high-speed systems that drill millions of parts per year to heavy-duty cells that move 25-ton workpieces. We collaborate closely with customers to understand their goals, develop practical automation solutions, and stand behind every system we deliver.

Building automation is not just about adding technology. It is about engineering smarter, more capable systems that evolve with our customers’ needs. At UNISIG, automation is never an afterthought. It is built in from the very beginning.

READY-ENGINEERED SYSTEMS: PROVEN AND SCALABLE

Standardized automation solutions make it easy for customers to say yes to automation, even without prior experience. UNISIG’s pre-engineered, proven automation eliminates unnecessary risk and development cost. We ask the right questions to help customers avoid common pitfalls and deliver automation systems that enhance productivity and competitiveness.

When multiple machines are connected in an automated system, centralized control simplifies operation and setup. The UNISIG Automation Cell Controller (ACC) provides a single interface that displays operation screens from every UNISIG machine in the cell, along with the robot sequence and parameters for the next job change.

ADVANCED EXPERTISE: SIMPLE UPGRADES TO COMPLEX CELLS

UNISIG has decades of experience designing and integrating automation, from ultra-high-speed systems that drill millions of parts per year to heavy-duty cells that move 25-ton workpieces. We collaborate closely with customers to understand their goals, develop practical automation solutions, and stand behind every system we deliver.

Building automation is not just about adding technology. It is about engineering smarter, more capable systems that evolve with our customers’ needs. At UNISIG, automation is never an afterthought. It is built in from the very beginning.

FREQUENTLY ASKED QUESTIONS

UNISIG offers a range of automation options, including in-machine conveyors, pallet systems, bulk feeders, robot integration, and multi-machine automation cells managed by the UNISIG Automation Cell Controller (ACC).

No. UNISIG provides ready-engineered and proven automation solutions. Our team guides customers through setup and operation to ensure a smooth transition into automated production.

Yes. Many UNISIG machines are designed to be automation-ready from the start, allowing customers to add automation systems as production needs grow.

Service parts excellence begins with a strong commitment to inventory. UNISIG maintains more than three million dollars in parts on hand to reduce or eliminate wait times for critical components.
12

Sep

UNISIG Service Parts Excellence

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LIFETIME OF SUPPORT BACKED BY OPERATIONAL EXCELLENCE

UNISIG builds precision deep hole drilling machines and automation. These are high-value products that represent a significant investment for our customers. Our service and parts teams help customers keep their machines running at their best for the entire life of the machine, often 20 years or more. That is why we focus on making service parts available quickly and reliably, ensuring long-term performance and uptime.

Committed, Managed, and Integrated Inventory

Service parts excellence begins with a strong commitment to inventory. UNISIG maintains more than three million dollars in parts on hand to reduce or eliminate wait times for critical components. But inventory alone is not enough; it must be actively managed. Our engineers use our synced PDM and ERP systems to build collections of service part needs, while materials management sets safety stock levels and minimum order quantities based on historical data and engineering insights. Service parts are also integrated directly into our production schedule, so replenishment is seamless and built into our operations rather than dependent on downtime or capacity.

Smart Storage and Fast Delivery

Storage and retrieval are equally critical. UNISIG uses Vertical Lift Modules, or VLMs, to store and retrieve parts with speed and precision, while larger parts are stored in our warehouse with the same ERP location sync. When orders are entered, VLM guides accurate retrieval, kitting, and preparation for shipment, whether for small tools, high-value components, or international freight. When an order is entered into the system, the required inventory is automatically picked and kitted for delivery. The VLM units make this process fast and efficient: a tray is retrieved, tilted toward the operator, and a laser pointer highlights the exact part needed. Smaller items like tools, seals, or accessories are easy to ship with standard methods. Larger orders may include heavy, high-value components that require dedicated trucks or international shipping, sometimes under export licenses. UNISIG has established procedures to minimize transit time for every shipment, no matter the size or destination.

Engineering Meets Operational Excellence

UNISIG has a reputation for engineering precision, but operational excellence is what ensures our customers’ long-term success. From large investments in parts inventory to integrated planning and advanced storage systems, we have built a service infrastructure designed to provide every machine and system we build with decades of reliable support. Choosing UNISIG means investing not just in a machine but in a partnership that delivers confidence and superior service.

Frequently Asked Questions

UNISIG machines are designed for decades of performance, and our service and parts teams provide support for the entire life of the machine.

We maintain more than three million dollars in inventory and use advanced planning systems to actively manage stock levels, safety stock, and replenishment to minimize downtime.

Beyond precision machine design, we invest in infrastructure, including inventory, planning, and logistics. This ensures every customer receives reliable long-term support and dependable service.

Landmann has managed UNISIG’s Midwest sales region for over a decade, during which his success has helped strengthen the company's worldwide reputation for delivering robust, customer-focused solutions to deep hole drilling applications.
08

Sep

UNISIG Promotes Steve Landmann to Vice President of Sales

Menomonee Falls, WI – September 8, 2025 – UNISIG Deep Hole Drilling Systems, a leading global manufacturer of deep hole drilling machines and automation systems, has promoted Steve Landmann to Vice President of Sales.

Landmann has managed UNISIG’s Midwest sales region for over a decade, during which his success has helped strengthen the company’s worldwide reputation for delivering robust, customer-focused solutions to deep hole drilling applications. His unique perspective is shaped by experience in predictive maintenance, machine building, and installation, giving him a deep understanding of customer challenges and long-term needs. In his new role, he will lead UNISIG’s sales team while working closely with management to maintain strong results, anticipate and adapt to evolving customer needs, and reinforce the company’s reputation for professionalism and solution-driven selling in high-value equipment markets.

“I’ve worked closely with Steve for more than 10 years and have always been impressed by his advocacy and dedication to our customers, his talent for solving complex problems, and his commitment to advancing UNISIG solutions,” said Anthony Fettig, CEO. “I’m confident he will provide outstanding leadership as he guides our sales team into the future.”

“I want UNISIG to lean even more heavily into what has always made us strong—an unwavering focus on the customer. That means putting customer needs, satisfaction, and complete care at the center of everything we do,” said Landmann. “My goal is to drive an almost obsessive customer focus that reinforces UNISIG’s reputation for innovation and solving the most complex deep hole drilling challenges.”

Landmann succeeds Jeff Price, who will retire in December, after more than 22 years as Vice President of Sales. Price played a pivotal role in the development of UNISIG, increasing its global footprint in the industry and driving the growth that enabled the company to continually expand its capabilities.

“Jeff’s leadership and dedication were instrumental in building UNISIG into the company it is today,” said Fettig. “We thank him for his many contributions and wish him the very best in retirement.”

About UNISIG
UNISIG is a leading manufacturer of deep hole drilling machines and automation systems. Engineered and manufactured in the USA, its machines serve industries ranging from aerospace to medical to moldmaking. Known for engineering innovation and in-house manufacturing capabilities, UNISIG combines precision, performance, and reliability in everything it delivers. For more information, visit www.UNISIG.com

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Steve Landmann has been promoted to Vice President of Sales at UNISIG. He has over a decade of experience managing the Midwest sales region, where he contributed significantly to strengthening UNISIG’s reputation for delivering robust, customer-focused solutions. In his new role, he will lead the global sales team and work closely with management to anticipate evolving customer needs and reinforce the company’s leadership in deep hole drilling solutions.

Landmann brings a unique perspective shaped by his experience in predictive maintenance, machine building, and installation. This hands-on background gives him a deep understanding of customer challenges and long-term needs, positioning him to continue UNISIG’s tradition of solution-driven selling in high-value equipment markets.

Landmann succeeds Jeff Price, who is retiring in December after more than 22 years as Vice President of Sales. Price played a pivotal role in UNISIG’s global footprint and long-term growth. This transition ensures continuity while also advancing UNISIG’s customer-focused strategy under new leadership.