Interview Questions for Mandrel Press Operation

Mandrel bending is a metal forming process that utilizes a precisely shaped tool, called a mandrel, to bend a tube or pipe into a specific radius and form. The process involves clamping one end of the tube to the mandrel, then applying pressure to the other end, forcing the tube to conform to the mandrel’s shape. Imagine trying to bend a drinking straw around a pencil – the pencil acts as the mandrel, guiding the straw into a curved shape. The principle lies in controlled plastic deformation of the material, ensuring a consistent bend radius without creasing or collapsing the tube.

Unlike simpler bending methods, mandrel bending ensures consistent wall thickness throughout the bend, avoiding thinning or buckling which can weaken the structure. This is crucial for applications requiring high strength and integrity.

Several mandrel bending processes exist, each suited to different materials, tube sizes, and desired bend geometries. Some common types include:

• Rotary Draw Bending: This method uses a rotating mandrel within a fixed die. The tube is pulled over the mandrel, forming the bend. It’s efficient for high-volume production and tight radius bends.
• Roll Bending: Three rolls, rotating at different speeds, gradually bend the tube. This is often used for larger diameter pipes and creating complex curves.
• Push Bending: A hydraulic press pushes the tube over a stationary mandrel. This method is versatile and suitable for various tube materials and sizes, but it might produce less consistent bends than rotary draw bending.
• CNC Mandrel Bending: Computer Numerical Control (CNC) machines offer precise and automated mandrel bending, enhancing repeatability and accuracy, especially important for complex shapes in high-precision applications.

Safety is paramount in mandrel press operation. Essential precautions include:

• Proper Personal Protective Equipment (PPE): Always wear safety glasses, gloves, and hearing protection. Depending on the specific operation, additional PPE such as a face shield or steel-toed boots might be necessary.
• Machine Guarding: Ensure all safety guards are in place and functioning correctly before operating the machine. Never bypass safety features.
• Lockout/Tagout Procedures: Before performing any maintenance or adjustments, follow proper lockout/tagout procedures to prevent accidental startup.
• Training and Competency: Only trained and authorized personnel should operate the mandrel press. Proper training ensures safe operation and prevents accidents.
• Emergency Shutdown Procedures: Be familiar with the location and operation of all emergency stop buttons and procedures.
• Material Handling: Use appropriate lifting equipment for heavy materials and avoid manual handling of excessively heavy or awkward loads.

Selecting the correct mandrel is crucial for successful bending. Factors to consider include:

• Tube Material and Diameter: Different materials have different bending characteristics. The mandrel’s diameter must match the tube’s internal diameter precisely to prevent damage or inconsistent bends.
• Bend Radius: The mandrel’s radius determines the final bend radius of the tube. A smaller mandrel radius will produce a tighter bend.
• Bend Angle: The mandrel’s length and design must accommodate the required bend angle.
• Bend Type: Different mandrels are designed for different bend types (e.g., U-bends, J-bends, or complex curves).
• Surface Finish: The mandrel’s surface finish affects the surface finish of the bent tube. A smooth mandrel minimizes surface scratching or marring.

For example, bending a thin-walled stainless steel tube requires a mandrel with a polished surface to avoid scratching. In contrast, a thicker walled carbon steel tube might tolerate a slightly rougher surface.

Die selection is equally critical in mandrel bending. The die works in conjunction with the mandrel to control the bending process and prevent wrinkling or cracking. Key considerations include:

• Die Material: The die material must be strong enough to withstand the bending forces and be resistant to wear.
• Die Design: The die design must be compatible with the mandrel and the desired bend geometry. Different die designs are suited for various bend angles and radii.
• Die Clearance: The clearance between the die and the mandrel must be appropriately chosen to avoid excessive friction or deformation. Incorrect clearance can result in uneven bends or damage to the tube or mandrel.
• Lubrication: The choice of lubricant is critical in reducing friction and preventing wear. The lubricant type depends on the material being bent.

Incorrect die selection can lead to several issues, such as uneven bends, tube wrinkling, or die breakage. The selection often requires experience and knowledge of the specific material properties and bending processes.

Measuring the accuracy of a bent part involves verifying several aspects:

• Bend Radius: Use a radius gauge or a digital caliper to measure the radius of the bend. Compare this with the specified dimension.
• Bend Angle: A protractor or angle gauge can measure the bend angle. Precision is important, and often a high degree of accuracy is needed.
• Wall Thickness: Check for any thinning of the wall thickness at the bend area using a micrometer. Consistent wall thickness ensures structural integrity.
• Straightness: Verify that the straight sections of the tube remain straight and true. Any deviations from straightness can affect the functionality of the part.
• Surface Finish: Inspect for surface defects like scratches, wrinkles, or kinks.

Depending on the application’s tolerance requirements, different measuring tools and techniques might be necessary. Precise measurements are usually documented in detailed inspection reports.

Several factors can contribute to defects in mandrel bending:

• Incorrect Mandrel Selection: Using a mandrel with an inappropriate diameter or radius can lead to inconsistent bends, wrinkles, or cracking.
• Improper Die Selection: Incorrect die clearance or a poorly designed die can result in uneven bending, wrinkling, or damage to the tube.
• Insufficient Lubrication: Lack of adequate lubrication can cause increased friction, leading to uneven bends, surface damage, and premature die wear.
• Excessive Bending Force: Applying excessive force can result in tube cracking, buckling, or permanent deformation.
• Material Defects: Pre-existing defects in the tube material (e.g., surface imperfections, inclusions) can be exacerbated during bending, leading to cracks or other flaws.
• Machine Malfunction: Mechanical issues in the mandrel press can lead to inconsistencies in the bending process. Regular maintenance is crucial.

Troubleshooting often involves careful inspection of the bent part, analyzing the process parameters, and reviewing the selection of mandrels, dies, and lubricants. Understanding the root cause is key to preventing future defects.

Troubleshooting mandrel press malfunctions requires a systematic approach. I begin by assessing the immediate problem – is the press not powering on, is there a bending issue, or is there a safety mechanism tripping? My troubleshooting process often follows these steps:

• Safety First: Always disconnect power and ensure the machine is locked out/tagged out before any inspection or repair.
• Visual Inspection: Check for obvious issues like loose connections, damaged wiring, hydraulic leaks, or obstructions in the machine’s movement path. A quick visual scan often reveals the culprit.
• Hydraulic System Check (if applicable): For hydraulic presses, I check fluid levels, pressure gauges, and look for leaks. Low fluid or pressure problems usually require refilling or addressing a leak.
• Electrical System Check (if applicable): I inspect fuses, circuit breakers, and wiring for any signs of damage or malfunction. A multimeter can be invaluable here.
• Mechanical Check: This involves checking the mandrel, tooling, and the press’s mechanical components for wear, damage, or misalignment. For example, a bent mandrel will result in inconsistent bends.
• Software/Control System Check (if applicable): For CNC mandrel presses, I’d look at error messages displayed on the control panel and check the programmed parameters for any inconsistencies. It could be a simple programming error.
• Systematic Elimination: If the problem persists, I systematically check each component, isolating the faulty part. This often involves process of elimination, testing each part of the system.

For example, I once worked on a press where the bending force was inconsistent. After a thorough check, we discovered a small crack in the hydraulic cylinder, leading to pressure loss. Replacing the cylinder resolved the problem.

My experience encompasses a wide range of mandrel materials, each with its own strengths and weaknesses. The choice of material depends heavily on the application, material being bent, and the required bend quality and longevity.

• Steel: The most common material, offering high strength and durability. Various grades of steel are available, offering different properties like hardness and wear resistance. For example, hardened tool steels are preferred for high-volume production or bending very hard materials.
• Aluminum: Lighter and easier to machine than steel, but less durable. Ideal for lower-strength applications or prototyping.
• Tungsten Carbide: Extremely hard and wear-resistant, perfect for high-temperature or abrasive applications. However, it’s brittle and expensive.
• Ceramics: Used in specialized applications requiring extremely high temperatures or chemical resistance. Their brittle nature limits applications.

In one project, we needed to bend a highly abrasive material. Steel mandrels wore out quickly. Switching to tungsten carbide mandrels drastically improved the tool life and reduced production costs.

Maintaining and cleaning a mandrel press is crucial for its longevity and safety. A regular maintenance schedule is essential.

• Regular Cleaning: Remove any debris, metal shavings, or lubricant residue from the machine’s components after each use. Compressed air is a good tool for cleaning hard to reach areas.
• Lubrication: Apply appropriate lubricants to moving parts as per the manufacturer’s recommendations. Regular lubrication minimizes wear and tear and ensures smooth operation.
• Inspection: Regularly inspect all components, including the mandrel, tooling, hydraulic lines (if applicable), and electrical components, for wear, damage, or leaks. Pay close attention to any wear patterns as they can indicate issues such as misalignment.
• Hydraulic System Maintenance (if applicable): This includes checking and maintaining fluid levels, filtering the hydraulic fluid, and inspecting the hydraulic hoses and seals for any signs of damage or leakage.
• Electrical System Maintenance (if applicable): This includes checking all electrical connections and wiring for any signs of damage or wear. It’s important to ensure all safety features are functioning correctly.

For instance, neglecting regular cleaning can lead to buildup of debris, hindering movement and causing premature wear of components.

The choice of lubricant in mandrel bending is crucial for preventing wear and ensuring a smooth bending process. Several types are used, depending on the materials involved and the application’s specifics:

• Water-based lubricants: Often used for ease of cleanup and environmental friendliness, particularly suitable for softer metals.
• Oil-based lubricants: Provide excellent lubrication and protection against wear, often preferred for heavier applications with harder materials. The specific type of oil (e.g., mineral oil, synthetic oil) will depend on the application and materials.
• Grease-based lubricants: Suitable for applications requiring long-lasting lubrication and protection, particularly in high-pressure or high-temperature situations.
• Specialized lubricants: Some applications may require specialized lubricants that provide additional properties, such as extreme pressure additives or corrosion inhibitors.

The correct lubricant ensures optimal bending while minimizing friction and wear.

Proper lubrication in mandrel bending is paramount for several reasons:

• Reduced Friction: Lubricants reduce friction between the mandrel, the material being bent, and other moving parts of the machine. This leads to smoother bending, improved accuracy, and reduced wear.
• Extended Tool Life: By reducing friction and wear, lubricants significantly extend the life of the mandrel and other machine components, reducing downtime and replacement costs.
• Improved Bending Quality: Reduced friction and smoother bending result in improved surface finish and reduced the risk of material damage or cracking.
• Increased Safety: Proper lubrication helps prevent unexpected machine malfunctions that could lead to accidents.

Imagine trying to bend a piece of metal without lubrication; it would require significantly more force, creating higher stress on the material and the machine and possibly causing damage. Lubricants act as a buffer, making the process smoother and safer.

Calculating the bending force required for a specific job isn’t a simple formula but rather involves considering several factors. There are various engineering formulas and software tools available to assist in this calculation.

Generally, the force calculation incorporates these factors:

• Material Properties: Yield strength, tensile strength, and modulus of elasticity of the material being bent are crucial.
• Bend Radius: The smaller the bend radius, the higher the required force.
• Material Thickness: Thicker materials require significantly more force.
• Bend Angle: Larger bend angles require more force.
• Mandrel Design: The mandrel’s geometry and material influence the required force. A smoother mandrel generally requires less force.

Many online calculators and software packages are available that can estimate the bending force given the inputs mentioned above. However, it’s always best to factor in a safety margin to account for variations and uncertainties. In my experience, field testing and fine-tuning based on empirical data are often necessary to refine the force calculations for optimal results.

I have extensive experience with CNC mandrel bending machines, utilizing their advanced capabilities to produce high-precision bends with repeatability and efficiency.

• Programming and Setup: I’m proficient in programming CNC mandrel benders, using CAD/CAM software to create and optimize bending programs. This includes specifying bending parameters such as force, speed, and bend angle.
• Operation and Maintenance: I understand the operation and maintenance of CNC mandrel benders. This includes regular inspections, calibration, and troubleshooting of any issues. I’m familiar with diagnostic tools available to identify issues promptly.
• Different Control Systems: I have experience with different control systems and interfaces common in CNC mandrel bending machines, enabling me to adapt quickly to new machines.
• Optimization: I’m adept at optimizing CNC bending programs to minimize cycle times, reduce material waste, and improve overall efficiency.

In a previous role, we implemented a new CNC mandrel bending machine. By optimizing the bending programs and implementing a robust maintenance schedule, we were able to increase our production efficiency by 30% and reduce material waste significantly.

Programming a CNC mandrel bending machine involves using specialized software to create a bending program that dictates the machine’s movements. This program translates the engineering drawing’s specifications into a set of precise commands. Think of it like creating a detailed recipe for the machine to follow.

The process typically starts with importing the CAD drawing or manually inputting the bend parameters. These parameters include the tube’s dimensions (diameter, wall thickness), material properties (yield strength, elasticity), bend radius, bend angle, and the desired final shape. The software then calculates the necessary machine movements, including the speed of the bending ram, the clamping pressure, and the precise path the mandrel follows to achieve the desired bend without damage.

Different CNC machines use different software interfaces, but common features include:

• Bend Radius Calculation: The software automatically calculates the appropriate mandrel size based on the desired bend radius and material properties. This is critical to preventing cracking or deformation.
• Bend Angle Control: Precise control of the bend angle is crucial for accuracy. The software ensures the machine stops at the exact angle specified in the program.
• Simulation: Many modern systems offer a simulation feature that visually previews the bending process. This allows operators to identify potential problems before actual bending commences, saving time and material.
• Error Detection: The software can detect potential errors, such as excessive bending forces or exceeding material limits, thus preventing machine damage or faulty parts.

For example, I once used a system where a slight miscalculation in the bend radius for a stainless steel component led to a minor crack during the initial bends. After correcting the parameters in the software, the subsequent parts were flawless. This highlights the importance of accurate programming and software verification.

Interpreting engineering drawings for mandrel bending requires a thorough understanding of both drafting conventions and the bending process itself. The drawing must clearly specify several key parameters:

• Tube Dimensions: Outside diameter (OD), inside diameter (ID), and wall thickness are crucial. Incorrect interpretation can lead to incorrect mandrel selection and failure.
• Material Specifications: The material type (e.g., steel, aluminum, brass) and its properties (yield strength, tensile strength) are needed for accurate bend radius calculation and to avoid material failure.
• Bend Radius: This specifies the radius of the bend. Smaller radii require more force and increase the risk of cracking.
• Bend Angle: The angle of the bend, precisely measured. Inaccurate measurements can lead to dimensional errors.
• Bend Sequence: For complex shapes, the order of bending is crucial. The drawing should specify the steps to ensure proper part formation and avoid stress concentrations.
• Tolerances: Acceptable variations in dimensions and angles must be clearly stated.

Imagine trying to bake a cake without a recipe – the result would be unpredictable. Similarly, without a clear understanding of the engineering drawing, the final bent part will likely deviate significantly from the design intent.

I often use a combination of CAD software and physical templates to verify the dimensions and bend sequence, particularly for intricate designs. This cross-checking ensures accuracy and reduces the chances of errors.

Quality control in mandrel bending is paramount because it directly impacts the structural integrity, functionality, and aesthetic appeal of the final product. It ensures that the bends meet the required specifications and are free from defects.

A robust quality control system involves:

• Regular Calibration: Ensuring that the bending machine’s sensors and measuring devices are accurately calibrated is crucial for maintaining consistent accuracy.
• Material Inspection: Inspecting the tube material for flaws, such as scratches or dents, before bending helps prevent defects and waste.
• Process Monitoring: Closely monitoring the bending parameters (force, speed, angle) during operation helps identify any deviations from the programmed settings.
• Dimensional Verification: Measuring the final product’s dimensions (bend radius, angle, overall length) using precision tools, ensuring they meet the tolerances specified on the engineering drawings. This often involves using CMMs (Coordinate Measuring Machines) for complex parts.
• Visual Inspection: Checking for surface imperfections (scratches, dents, cracks) is crucial, especially for applications where aesthetics are important.

In a past project, implementing a stricter quality control procedure resulted in a significant reduction in scrap rate, saving both time and materials. Ignoring quality control can lead to significant losses, potential safety hazards, and reputational damage.

My experience encompasses a wide range of tube materials, each with unique properties affecting the mandrel bending process. These include:

• Mild Steel: Relatively easy to bend, but susceptible to cracking if not handled carefully. Careful control of bending speed and force is required.
• Stainless Steel: Stronger and more resistant to corrosion, but more challenging to bend due to its higher yield strength. Requires more force and potentially specialized tooling to avoid damage.
• Aluminum: Lightweight and easy to bend, but prone to wrinkling if not properly supported. Careful mandrel selection is crucial.
• Copper and Brass: Relatively ductile, but may work-harden with multiple bends. Proper lubrication can help.
• Titanium: High strength-to-weight ratio but challenging to bend due to its high yield strength and tendency to crack. Requires precise control and specialized tooling.

Each material requires a different approach. For example, stainless steel often requires lubrication to minimize friction and reduce the risk of cracking. Aluminum might need tighter clamping to avoid wrinkling. The choice of mandrel material and its surface finish also needs consideration to prevent scratches or galling.

Different tube wall thicknesses significantly impact the mandrel bending process. Thicker walls require greater bending force and are more prone to cracking, while thinner walls are more susceptible to wrinkling or collapsing. The choice of mandrel diameter and the bending technique must be adapted based on the wall thickness.

For example:

• Thicker Walls: Requires a larger mandrel radius and slower bending speed to reduce stress concentrations and the risk of cracking. The machine may need to be adjusted to deliver higher bending forces.
• Thinner Walls: Requires a smaller mandrel radius but more careful clamping to avoid collapsing the tube. The bending speed might need to be increased to minimize the risk of wrinkling.

I frequently employ different bending strategies based on the wall thickness. For thicker-walled tubes, I often use a more gradual approach, allowing the material to deform more slowly. For thinner-walled tubes, I might opt for faster bending speeds and tighter clamping.

Accurate knowledge of the tube’s yield strength and elastic limit is crucial for determining the correct bending parameters.

Springback in mandrel bending refers to the elastic recovery of the tube after the bending force is removed. Imagine bending a flexible ruler – it doesn’t stay bent at the exact angle you’ve imposed, it springs back slightly. This phenomenon is due to the elastic properties of the material.

The degree of springback depends on several factors, including:

• Material Properties: Materials with higher elasticity will exhibit greater springback.
• Bend Radius: Smaller bend radii generally result in more significant springback.
• Wall Thickness: Thicker walls generally show less springback compared to thinner walls.
• Bending Speed: Faster bending speeds can contribute to increased springback in some cases.

Understanding and accounting for springback is essential to achieving the desired final shape.

Compensating for springback involves predicting the amount of elastic recovery and adjusting the bending angle accordingly before the bend is made. This requires careful calculation and often relies on experience and empirical data or specialized software.

Several methods are used to compensate for springback:

• Overbending: Intentionally bending the tube beyond the desired final angle to account for the expected springback. This approach requires precise knowledge of the material properties and the bending process.
• Springback Tables and Software: Many bending machines utilize software that incorporates springback models to calculate the required overbend angle. These models are often based on material properties and empirical data.
• Trial and Error: In some cases, particularly with less predictable materials or complex shapes, a trial-and-error approach might be necessary. This is usually more time-consuming and requires close monitoring.
• Post-Bend Adjustment (Rare): In certain cases, minor adjustments can be made after the bending process using other tools or techniques; however, this is generally not preferred and can introduce additional stresses to the part.

In practice, I often combine overbending with the use of springback compensation software to ensure high accuracy and minimize the need for rework. Accurate springback prediction is crucial for ensuring the final part meets the required specifications.

My experience encompasses a wide range of bending dies used in mandrel press operations. I’ve worked extensively with various designs, each suited for specific material properties and bend geometries. This includes:

• Standard V-Dies: These are the most common, offering simple and efficient bending for relatively straightforward shapes. I’ve used these for numerous projects involving mild steel and aluminum.
• Gooseneck Dies: Ideal for creating tight radius bends, particularly useful when working with more rigid materials or when a very precise bend is needed. I successfully employed gooseneck dies on a project involving stainless steel tubing.
• Multi-Stage Dies: These allow for complex bends in a single operation, reducing cycle time and increasing productivity. I’ve utilized these for producing intricate shapes in high-volume manufacturing settings.
• Specialty Dies: This category includes custom-designed dies for unique applications and challenging bends. One such project involved a custom die created to bend a unique alloy with specific material limitations.

My experience extends to understanding die material selection—choosing the right steel alloys to resist wear and tear based on the application’s demands—and the critical relationship between die design, material properties, and press tonnage.

Inspecting mandrels and dies for wear and tear is crucial for preventing costly errors and ensuring safe operation. My inspection process involves a multi-step approach:

• Visual Inspection: This is the first step, carefully examining the mandrel and die surfaces for scratches, cracks, dents, or any signs of deformation. I pay close attention to areas subject to high stress and friction.
• Dimensional Check: Using precision measuring tools like calipers and micrometers, I verify the dimensions of the mandrel and die against specifications. Any deviation could indicate wear and affect bend accuracy.
• Surface Finish Examination: I check the surface finish for roughness or pitting, which can negatively affect the quality of the bent part. A smooth surface ensures consistent part quality.
• Hardness Testing (when applicable): For dies made of hardened steel, I use a hardness tester to assess whether the material has softened due to wear, indicating a need for replacement or refurbishment.

Beyond routine checks, any unusual noise, vibration, or difficulty in operation triggers a thorough inspection. Regular preventative maintenance is vital, and I always document my findings.

Regular maintenance of mandrel bending equipment is essential for optimal performance and safety. My routine includes:

• Lubrication: Applying the correct type and amount of lubricant to all moving parts, including the press ram, slides, and die mechanisms, to reduce friction and wear. This is done according to the manufacturer’s guidelines and the type of lubricant specified for the application.
• Cleaning: Removing debris and metal shavings from the machine and dies after each operation. This is a crucial step to prevent damage and ensure smooth operation. Compressed air and appropriate cleaning solvents are used depending on the material being processed.
• Inspection of Hydraulic System (if applicable): Checking fluid levels, pressure, and for any leaks in the hydraulic system. This ensures efficient operation and prevents unexpected downtime.
• Regular Tightening of Bolts and Fasteners: Checking for loose bolts and nuts, especially on the die clamping mechanisms. Loose fasteners can cause misalignment and affect bend accuracy.
• Electrical System Check (if applicable): Verifying the proper operation of electrical components, switches, and safety interlocks to ensure the machine operates as intended and complies with safety standards.

I also create and maintain a detailed maintenance log, recording all procedures, inspections, and any necessary repairs or replacements.

Safety is paramount in mandrel press operation. My approach emphasizes proactive measures:

• Personal Protective Equipment (PPE): Always using appropriate PPE including safety glasses, hearing protection, and gloves, as well as steel-toed boots.
• Lockout/Tagout Procedures: Strictly adhering to lockout/tagout procedures before performing any maintenance or repair work on the machine to prevent accidental activation.
• Proper Machine Operation: Ensuring proper machine operation by following the manufacturer’s guidelines, and never exceeding the machine’s rated capacity.
• Safe Handling of Materials: Carefully handling materials to prevent injuries. This includes proper lifting techniques and using material handling equipment as needed.
• Emergency Procedures: Being familiar with emergency procedures and the location of safety equipment, such as emergency stop buttons and fire extinguishers.
• Regular Safety Training: Participating in regular safety training and keeping updated on the latest safety standards and best practices.

I actively promote a safety-conscious work environment, reporting any unsafe conditions or practices immediately.

During a high-volume production run, we experienced inconsistent bend angles on a specific part. After initially checking the die for wear and tear (which was minimal), I systematically investigated:

1. Die Alignment: I meticulously checked the die alignment using precision measuring tools and found a slight misalignment causing the inconsistent bends. This was corrected by adjusting the die set screws.
2. Press Calibration: I verified the press’s calibration, ensuring the tonnage was consistently applied throughout the bending cycle. Slight adjustments were made using the press’s calibration controls.
3. Material Consistency: I then examined the material itself, verifying its properties matched the specifications. This ruled out any inconsistencies in the material affecting the bend.

By systematically eliminating possibilities, we identified the misalignment as the root cause, resolving the issue and ensuring consistent part quality. This experience highlighted the importance of methodical troubleshooting and the need to consider all potential factors impacting the bending process.

My strengths include my meticulous attention to detail, my problem-solving skills, and my commitment to safety. I am highly proficient in operating mandrel presses, performing maintenance, and troubleshooting issues. I am also a quick learner, adapting easily to new equipment and techniques.

One area I am working to improve is my experience with more advanced CNC mandrel bending systems. While I have a basic understanding, further training in this area would enhance my skillset and allow me to contribute to a wider range of projects.

My salary expectations for this role are in the range of [Insert Salary Range], commensurate with my experience and skills, and taking into account the responsibilities and compensation offered by your organization. I am open to discussion and flexible, based on a comprehensive review of the total compensation package.