Precision vs accuracy in machining shapes how engineers design parts and how suppliers deliver them. Many people use these terms as if they mean the same thing. That confusion often leads to poor tolerance decisions, unstable quality, assembly issues, and avoidable production costs.
If you need CNC parts that fit, function, and repeat reliably, you need to understand both concepts clearly. This guide explains what precision and accuracy really mean in machining, how they affect quality and cost, and how you can apply them when reviewing drawings, tolerances, inspection results, and supplier capability.
What Is Precision in Machining?
Precision in machining refers to the ability to consistently produce the same result. When repeated measurements stay very close to one another, the machining process shows good precision. In other words, precision is about consistency, not just one successful result. For example, if a shaft has a target diameter of 20.00 mm and repeated parts measure 19.98, 19.98, 19.99, and 19.98 mm, the process shows good precision because the results stay very close to one another.
In CNC machining services, precision is reflected in repeatability. If a machine cuts the same diameter, hole, slot, or surface feature with very little variation across multiple parts, the process is precise. The closer those repeated results cluster together, the higher the precision.
Precision also connects to reproducibility. A process is more reliable when it can maintain that same consistency across different setups, batches, or production runs. This matters in real manufacturing because customers do not buy only one good part. They need parts that perform the same way every time.
What Is Accuracy in Machining?
Accuracy in machining means how close a measured result is to the intended dimension or target value. If a CNC process produces a feature that closely matches the drawing requirement, that result is accurate. In simple terms, accuracy tells you whether the part hits the target.
In machining work, you judge accuracy by comparing the finished result with the nominal dimension, geometric requirement, or specified tolerance on the drawing. If a bore is designed to be 20.00 mm and the measured result is 20.00 mm or very close to it within the allowed tolerance, the machining result is accurate.
Accuracy matters because the drawing defines functional intent. A bore must fit a mating shaft. A hole pattern must align with other parts. A sealing surface must sit within the required limit. If the measured result drifts too far from the target, the part may still look acceptable, but it may fail in assembly or performance.
Key components of accuracy include:
- Bias: Bias is the difference between the measured average and the true or reference value. It helps identify systematic offset in the process or measurement system, such as a machine or gauge that consistently reads high or low.
- Stability: Stability describes whether results remain reliable over time under the same conditions. It helps show whether an accurate process stays accurate across hours, shifts, or production runs instead of drifting.
- Linearity: Linearity shows whether measurement accuracy stays consistent across the full measurement range. It helps confirm that a gauge or process does not perform well in one dimension but loses accuracy at another.
Why Precision and Accuracy Matter in Machining Projects?
Precision and accuracy matter in machining projects because they directly affect part quality, process stability, and production cost. Accuracy helps a part meet the drawing, while precision helps the process repeat that result consistently. If either one is weak, the risk of scrap, rework, assembly issues, and customer complaints rises quickly.
Improved Product Quality
Product quality improves when a machining process delivers both precision and accuracy. Accuracy keeps the part close to the target dimension, while precision keeps repeated results consistent across multiple parts. When these two work together, the shop can produce parts that not only meet the drawing, but also maintain stable quality from one piece to the next.
This improvement appears in several practical ways. Dimensions stay within tolerance more reliably. Hole positions, bore sizes, slot widths, and mating surfaces remain closer to design intent. At the same time, part-to-part variation becomes smaller, which helps assemblies fit more consistently and reduces unexpected quality issues during inspection or use.
Better Part Fit and Assembly
Machined parts rarely work alone. Most of them must fit with another part, align with a mating surface, or hold a defined position in a larger assembly. If accuracy is poor, the part may miss the target dimension. If precision is poor, different parts may fit differently from one unit to the next.
This becomes critical in holes, shafts, bores, sealing faces, and mounting features. A small shift in one feature may create looseness, interference, leakage, noise, or uneven wear. In complex assemblies, one unstable dimension can affect the whole system.
Lower Costs and Higher Efficiency
Precision and accuracy have a direct effect on manufacturing cost. When a process stays stable and on target, the shop spends less time on adjustments, sorting, rework, and repeated inspection. That improves throughput and reduces hidden production waste.
Higher efficiency does not only mean faster cutting. It also means smoother process flow. Stable machining reduces machine downtime, operator intervention, and quality interruptions. Over time, that creates a more predictable and cost-effective production environment.
Reduced Scrap and Rework
Scrap and rework often come from dimensional variation and missed targets. When a process cannot repeat reliably or cannot stay close to nominal, more parts fall outside tolerance or require correction. That increases material waste, labor time, and delivery risk.
This issue matters even more with expensive materials and tight-tolerance parts. Reworking aluminum may be manageable in some cases. Reworking titanium, hardened steel, or thin-wall parts is often more difficult and more costly. Good precision and accuracy reduce those avoidable losses at the source.
Greater Safety and Compliance
In some industries, poor machining quality is not just a cost issue. It becomes a safety and compliance issue. Aerospace components, medical devices, and critical automation parts often rely on controlled dimensions to maintain structural integrity, motion accuracy, or sealing performance.
A feature that drifts out of range can affect how safely the product operates. It can also create compliance problems when parts must meet strict regulatory, customer, or internal quality requirements. This is one reason high-precision machining matters so much in controlled sectors.
More Reliable Testing and Prototyping
Prototype parts must support design validation. If a prototype is dimensionally unstable or off target, test results become harder to trust. Engineers may think the design failed when the real issue came from machining variation rather than design intent.
Reliable prototyping depends on both accuracy and precision. Accuracy helps the test part represent the intended design. Precision helps confirm that the result is not a one-off success. This becomes especially important when teams compare multiple design iterations or prepare for pilot production.
Stronger Customer Trust and Satisfaction
Customers expect more than one acceptable sample. They expect stable quality, clear inspection results, and repeatable performance across future orders. When a supplier demonstrates both precision and accuracy, the customer gains more confidence in the process and the partnership.
That trust matters in machining projects. Buyers often evaluate suppliers based on consistency, communication, and quality control discipline, not only on quoted price. A supplier that can hold target dimensions and repeat them reliably is easier to trust for long-term production.
Precision vs Accuracy in Machining: What Is the Difference?
The difference between precision and accuracy lies in consistency versus correctness. Accuracy shows how close a result is to the target value on the drawing. Precision shows how closely repeated results match one another. In machining, you need both to produce parts that meet specifications and remain stable across repeated runs.
Types of Error Indicated
Precision and accuracy reveal different error patterns in machining. Accuracy usually helps identify whether the process is drifting away from the intended target, while precision helps show whether repeated results remain stable or start to scatter. In practice, engineers often look at two main error types when they evaluate machining performance:
- Systematic error is connected to accuracy because it creates a repeated shift away from the target. Typical sources include calibration drift, incorrect offsets, machine geometry issues, thermal expansion, and measurement bias.
- Random error has a stronger link to precision. Instead of pushing results in one fixed direction, it increases scatter between repeated measurements. Setup instability, vibration, fluctuating cutting forces, tool wear, and material variation often contribute to this pattern.
Measurement Focus
Accuracy centers on closeness to the target value. It shows whether the machined feature matches the nominal dimension, position, or geometric requirement on the drawing. In machining, this matters when you need to confirm that the part meets the intended design value.
Precision centers on consistency across repeated results. It shows whether multiple measurements stay closely grouped during repeated machining cycles or across multiple parts. This matters when you need the process to remain stable, repeatable, and reliable in production.
Number of Measurements
Accuracy can often be discussed from a single measured result, as long as you compare that result with the target dimension or requirement. Precision usually needs multiple measurements because you cannot judge consistency from only one result.
In production machining, this difference becomes very important. One part can appear accurate, but only repeated data can show whether the process is actually precise. That is why batch inspection, capability review, and repeated sampling matter so much in quality control.
Impact on Part Quality
Accuracy affects whether the part conforms to the drawing. If accuracy is poor, the part may miss a required size, position, or form and fail in assembly or function. Precision affects whether that quality level remains stable across multiple parts.
When both are strong, part quality becomes more dependable. Features stay close to the target, and variation remains controlled from piece to piece. If accuracy is weak, you may produce the wrong part. If precision is weak, you may produce unstable quality.
Measurement Tools
Accuracy usually relies on calibrated instruments such as calipers, micrometers, bore gauges, height gauges, gauge blocks, and CMM systems. These tools help verify whether the measured result is truly close to the target value.
Precision often relies on high-resolution instruments such as micrometers, dial indicators, digital indicators, comparators, and fine-resolution bore gauges. These tools help detect small variations and show whether repeated results stay tightly grouped.
Relationship to Tolerance
Accuracy refers to how close a measured result is to the nominal value within the specified tolerance range. In machining, this means the actual dimension needs to stay near the target value, not just somewhere inside the allowed limit.
Precision refers to how consistently repeated results remain within that same tolerance range. In high-precision machining, tolerances can be held as tight as ±0.0254 mm, provided the process has strong control over machine capability, tooling, material behavior, setup, and inspection.
Comparison Table of Precision vs Accuracy
| Comparison Point | Accuracy | Precision |
| Error pattern | shifted from the target | scattered results |
| Measurement priority | target value | result consistency |
| Data requirement | one result or average | repeated measurements |
| Quality effect | drawing conformance | process stability |
| Instrument emphasis | calibrated tools | high-resolution tools |
| Tolerance behavior | close to nominal | grouped within limits |
Four Typical Precision and Accuracy Outcomes in Machining
Machining results usually fall into four common patterns when you compare precision and accuracy together. Below, we use 10.00 mm as the reference dimension to show the four typical precision and accuracy outcomes in machining. Using the same baseline makes it easier to see whether the process is close to the target, consistent across repeated parts, both, or neither.
Precise and Accurate
A process is both precise and accurate when repeated measurements stay tightly grouped and remain very close to 10.00 mm. For example, if several shafts measure 10.00, 10.01, 10.00, and 9.99 mm, the process shows both good target control and good consistency.
This is the ideal machining condition. The results stay near the nominal size, and the variation remains small from part to part. The process hits the target and repeats the result reliably.
Accurate but Not Precise
A process is accurate but not precise when the average result is close to 10.00 mm, but the individual measurements vary too much. For example, several shafts may measure 9.96, 10.03, 10.01, and 10.00 mm. The average is near the target, but the spread between parts is wider than expected.
This means the process can reach the right value overall, but it does not do so consistently. In production, this creates instability because some parts may fit well while others begin to drift. The target is reached on average, but the process lacks repeatability.
Precise but Not Accurate
A process is precise but not accurate when repeated measurements stay closely grouped, but the whole group sits away from 10.00 mm. For example, several shafts may measure 10.04, 10.04, 10.05, and 10.04 mm. The process is very consistent, but it is consistently missing the target.
This pattern usually points to a fixed offset in the process. The machine may have a calibration issue, a tool offset problem, or a setup reference error. Even so, this condition is often easier to correct than a highly unstable process because the variation is already controlled. The process repeats well, but it repeats the wrong result.
Neither Precise nor Accurate
A process is neither precise nor accurate when the measurements are scattered and also remain far from 10.00 mm. For example, several shafts may measure 9.94, 10.06, 9.97, and 10.05 mm. The results show both poor grouping and poor closeness to the target.
This is the weakest process condition. The shop cannot rely on the output because the process is unstable and off target at the same time. In real machining, this usually leads to high scrap, repeated adjustments, and low confidence in batch production. The process misses the target and fails to repeat consistently.
What Affects Precision and Accuracy in CNC Machining?
Precision and accuracy in CNC machining depend on different but related process conditions. Precision is more closely tied to repeatability and variation control, while accuracy is more closely tied to target alignment and dimensional correctness. When engineers clearly separate these two sides, they can diagnose machining problems more effectively.
What are the Factors Affecting Precision?
Precision is affected by how consistently the machining process repeats the same result under the same conditions. When variation stays low from one cycle to the next, the process shows better precision. In CNC machining, this usually depends on repeatable machine movement, stable part location, consistent clamping, and controlled tool behavior.
Machine Repeatability
Machine repeatability refers to the ability of the machine to return to the same position every cycle. If axis motion changes slightly during repeated runs, dimensions may begin to spread even when the program remains the same. This matters because precision depends on tight grouping between repeated results. A machine with strong repeatability is more likely to produce stable features across multiple parts and support consistent production output.
Setup Consistency
Setup consistency affects whether each workpiece begins from the same reference position. If loading, alignment, or datum contact changes between setups, repeated dimensions may vary even when the machining path does not change. This directly affects precision because the process can no longer repeat the same result closely. Better setup consistency helps keep measurements grouped and improves repeatability across batches, operators, and production runs.
Fixturing Consistency
Fixturing consistency affects how securely and repeatedly the workpiece is held during machining. If the fixture allows slight movement, uneven seating, or variable clamping force, repeated results may no longer stay tightly grouped. That reduces precision because each part experiences a slightly different machining condition. A stable fixture supports repeatable positioning and helps the process maintain closer consistency across repeated parts, especially on tight-tolerance features.
Tool Wear Stability
Tool wear stability affects whether the cutting tool removes material in a consistent way over time. As the tool wears, edge condition and cutting forces may change, which can increase variation between repeated parts. This weakens precision because the process no longer repeats the same result as closely as before. Stable and predictable tool wear helps maintain tighter grouping across repeated measurements and supports more consistent production performance.
What are the Factors Affecting Accuracy?
Accuracy depends on how close the machining result stays to the intended target value. In CNC machining, good accuracy comes from process conditions that keep the actual dimension aligned with the drawing. Even a stable process can miss the nominal value if offsets, calibration, or material response shift the result. This is why accuracy is closely tied to target conformance rather than repeated consistency alone.
Calibration
Calibration affects whether the machine and measurement system stay aligned with known standards. If calibration drifts, the process may keep producing results that look consistent but remain offset from the target value. This directly reduces accuracy because the measured or machined dimension no longer reflects the true nominal requirement. Good calibration helps keep the process centered and improves confidence that the actual result matches the drawing.
Cutting Parameters
Cutting parameters influence how the tool interacts with the material and how the final dimension is formed. Feed rate, spindle speed, depth of cut, and tool path can all shift the result away from nominal if they are not set correctly. Poor parameter selection may increase deflection, heat, or unstable cutting behavior. These effects reduce accuracy by changing how closely the finished feature matches the intended target size.
Material Properties
Material properties affect accuracy because different materials respond differently during machining. Hardness variation, internal stress, thermal expansion, and elastic recovery can all shift the final dimension away from nominal. The same program may not produce the same true result in aluminum, stainless steel, or engineering plastics. That is why engineers must consider material behavior carefully when they evaluate dimensional accuracy, especially on thin-wall or high-tolerance features.
Industries That Require High Precision and Accuracy in Machining
High precision and high accuracy matter most in industries where dimensional error can affect safety, function, reliability, or regulatory compliance. In these sectors, machining quality is not only about meeting a drawing. It also supports assembly performance, product life, traceability, and process control across repeated production.
Aerospace and Aviation
Aerospace and aviation parts often work under high stress, tight fit requirements, and strict quality controls. Common aerospace parts include brackets, housings, bushings, shafts, valve bodies, actuator parts, and structural interfaces. These features need strong dimensional control to support alignment, sealing, load transfer, and reliable assembly.
In this field, even small dimensional errors can create larger system risks. That is why aerospace machining usually demands both strong accuracy to meet the design target and strong precision to maintain consistency across repeat production.
Automotive Systems and Components
Automotive components depend on controlled dimensions to support fit, motion, sealing, and long-term durability. This applies to transmission parts, engine components, sensor housings, brake system parts, and many other machined features used in assemblies.
Precision and accuracy both matter because automotive production often combines tight tolerances with high volume. The part must meet the target dimension, and the process must repeat that result consistently across many units, not just a few approved samples.
Medical Devices and Surgical Components
Medical devices and surgical components often require very controlled dimensions because they interact with critical systems, sensitive assemblies, or the human body. Parts such as surgical tools, instrument housings, implant-related components, and precision connectors rely on stable machining quality.
In this type of work, poor accuracy can affect function, while poor precision can weaken repeatability across batches. That is why medical machining usually places strong emphasis on dimensional control, inspection reliability, and process consistency.
Robotics and Automation Equipment
Robotics and automation equipment rely on precise motion, stable positioning, and repeatable mechanical performance. Components such as guide parts, motor housings, end-effector parts, mounts, and alignment features need dependable machining quality to support smooth movement and accurate assembly.
These systems often include many interrelated parts, so small dimensional variation can affect the performance of the full mechanism. High precision and accuracy help maintain alignment, reduce vibration, and support reliable operation over repeated cycles.
How Precision and Accuracy Are Measured in CNC Machining?
Precision and accuracy in CNC machining are measured by comparing actual part data with repeatability and target requirements. Accuracy focuses on how close the result is to the nominal value, while precision focuses on how closely repeated results match one another. In practice, both require reliable inspection methods and trustworthy measurement equipment.
Measuring Precision
Precision is measured by taking repeated measurements of the same feature under the same conditions. The inspector measures the same diameter, hole, slot, or surface position several times, or measures the same feature across multiple parts from the same batch. If those results stay tightly grouped, the process shows good precision.
In practical machining work, shops often use micrometers, dial indicators, bore gauges, digital indicators, comparators, or CMMs to check this variation. The focus is not the nominal value itself. The focus is on the spread between repeated results. A smaller spread means better repeatability and better precision.
Measuring Accuracy
Accuracy is measured by comparing the measured value with the true value or reference value. A simple way to express it is:
Accuracy = [(measured value − true value) / true value] × 100%
This formula shows the percentage difference between the actual measurement and the target value. In machining, the smaller this percentage is, the closer the result is to the required dimension, which means the process shows better accuracy. If the difference becomes larger, the machined feature moves farther away from the intended size or position.
In practical CNC inspection, the true value is usually treated as the nominal dimension on the drawing or a calibrated reference standard. The measured value comes from inspection tools such as micrometers, calipers, bore gauges, height gauges, or CMM systems. After measurement, the inspector compares the result with the target to determine whether the feature remains close enough to design intent.
How to Improve Both Precision and Accuracy in Machining?
Improving precision and accuracy requires better control over design, setup, tooling, and machining conditions. Accuracy improves when the process stays closer to the target value. Precision improves when repeated results stay more consistent. In practice, shops need both process correction and process stability to achieve reliable machining quality.
Optimize Part Design
Part design affects how easily a shop can hold precision and accuracy. Clear datums, realistic tolerances, and simpler feature geometry reduce machining difficulty and make inspection more reliable. Overly complex features or unnecessarily tight tolerances increase variation and correction work. A better design makes the process easier to control and improves the chance of producing parts that are both close to the target and consistent across repeated runs.
Strengthen Machine Calibration
Machine calibration helps keep the process aligned with the intended target value. If calibration drifts, the machine may still repeat well, but continue producing the wrong result. Good calibration improves accuracy by reducing offset error. It also supports precision because a properly aligned machine is easier to control over repeated cycles. In production machining, calibration is one of the most basic requirements for stable dimensional performance.
Improve Tool Selection
The right tool helps improve accuracy by keeping the cut closer to the target dimension, and it helps improve precision by making repeated cuts more consistent. Shops usually choose tools based on the material, feature type, and tolerance requirement. Common options include end mills for profiles and pockets, drills for holes, reamers for tighter hole size control, and boring tools for better bore accuracy. A more suitable tool geometry, diameter, and wear resistance help the process stay both closer to nominal and more repeatable.
Optimize Cutting Parameters
Cutting parameters and CNC programming, including G-codes and M-codes, both affect accuracy and precision. G-codes control tool movement and path geometry, while M-codes control machine functions such as the spindle and coolant. When feed rate, spindle speed, depth of cut, and programmed tool paths are set correctly, the process stays closer to the target dimension, and repeated results remain more consistent.
Standardize Setup
Setting up standardization helps each part begin from the same condition. When loading position, datum reference, clamping method, and zero-point procedure stay consistent, the process becomes easier to repeat and control. This directly supports precision by reducing variation between parts. It also supports accuracy because stable setup conditions make it easier for the machining result to stay close to the intended target. Consistent setup is especially important in batch production.
How Precision and Accuracy Affect Drawing and Tolerance Decisions?
Precision and accuracy directly influence how engineers should define dimensions, datums, and tolerances on a drawing. If drawing requirements do not match real machining capability, the part becomes harder to make, inspect, and control. Good drawing decisions help the supplier hold the target more accurately and repeat the result more precisely.
Critical Dimensions
Accuracy and precision directly affect how engineers define critical dimensions on a drawing. If a dimension controls fit, sealing, alignment, motion, or assembly, it usually needs a tighter tolerance because even a small deviation can affect part function. In this case, accuracy matters because the machined result must stay close to the target value, while precision matters because repeated parts must hold that result consistently.
This also changes tolerance decisions. Critical dimensions often require tighter control than non-critical features, but the tolerance still needs to match actual machining capability. If the requirement is tighter than necessary, cost and scrap risk increase. If it is too loose, the part may fail in use. Good drawing decisions place tighter tolerances on truly critical dimensions, where both accuracy and precision have the greatest functional impact.
Datum Selection
In datum selection, accuracy affects whether the chosen datum can control a feature close to its intended functional location, while precision affects whether that same reference can support repeatable machining and inspection. This influences drawing and tolerance decisions because critical features usually need datums that are both functionally meaningful and stable enough for repeated use.
When precision and accuracy requirements are higher, engineers often need clearer datum structures and tighter control of features referenced from those datums. Better datum selection helps drawings reflect real functional intent and makes tolerance decisions more practical and controllable.
Tolerance Allocation
In tolerance allocation, accuracy determines how close a feature must stay to the nominal value, while precision determines how consistently that feature must be maintained across repeated parts. Critical features usually need tighter tolerances because they directly affect fit, function, or assembly.
Higher precision and accuracy requirements call for more careful tolerance distribution on the drawing. Well-planned drawings place tighter tolerances on critical features and wider tolerances on non-critical ones, which makes machining control more practical and cost-effective.
Common Mistakes in Precision and Accuracy Control
Many machining problems come not from machine limits alone, but from mistakes in how precision and accuracy are understood and controlled. Some errors shift the result away from the target, while others increase variation between repeated parts. Recognizing these common mistakes helps engineers and suppliers make better drawing, setup, and inspection decisions.
Confusing Precision with Accuracy
Many people treat precision and accuracy as the same thing, but they control different aspects of machining quality. A process can repeat the same result very well and still miss the target. It can also hit the target once without showing stable repeatability.
This confusion often leads to poor decisions in quoting, inspection, and process control. When teams fail to separate consistency from target conformance, they may solve the wrong problem or overlook the real source of variation.
Overlooking Tolerance Requirements
Some quality issues come from focusing on nominal dimensions without paying enough attention to the actual tolerance range. A part may appear close to the target, but if the allowed tolerance is very tight, even a small deviation can become unacceptable.
This mistake also appears in drawing review and production planning. If tolerance requirements are not read carefully, the shop may underestimate machining difficulty, inspection needs, or process risk. Clear tolerance awareness is essential for both accuracy and precision control.
Using Inconsistent Measurement Methods
Measurement inconsistency can distort the real condition of the machining process. Different operators may use different tools, contact pressure, measuring points, or inspection habits. As a result, the same feature may produce different readings even when the part itself has not changed.
That problem makes process control much harder. Precision may appear worse than it is, or accuracy may appear better than it is. Reliable machining decisions depend on repeatable measurement practice, not only on having good instruments available.
Ignoring Tool Wear
Tool wear changes the cutting edge over time, and that change affects dimensional results. Early parts in a batch may look stable, while later parts begin to drift from the target or show more variation. This pattern is common in repeated production, especially on tighter-tolerance features.
Unchecked wear can reduce accuracy by shifting the result away from nominal. It can also reduce precision by making part-to-part output less consistent. Regular tool monitoring helps maintain both target control and repeatability throughout the run.
Conclusion
Precision and accuracy in machining work together, but they do not mean the same thing. Accuracy keeps a feature close to the target value, while precision keeps repeated results consistent across parts and batches. When both are controlled well, machining quality becomes more reliable, assemblies fit better, and production risk becomes easier to manage.
DZ Making supports custom CNC machining projects with practical engineering review and stable production control. Contact us for a quote or manufacturability review if you need machined parts with reliable precision and accuracy.
FAQs
1. Is precision the same as accuracy in machining?
No. Precision and accuracy describe different aspects of machining quality. Accuracy shows how close a result is to the target value, while precision shows how consistent repeated results are. A process can be precise without being accurate, and it can also be accurate once without being consistently precise.
2. Can a machined part be precise but not accurate?
Yes. This happens when repeated measurements stay closely grouped, but the whole group sits away from the target value. In machining, that usually means the process is stable but centered incorrectly. Common causes include calibration drift, offset error, or an incorrect setup reference.
3. How do tolerance and accuracy relate in CNC machining?
Tolerance defines the allowable variation around a nominal value, while accuracy shows how close the actual result is to that target. A part may fall within tolerance, but better accuracy means it stays closer to nominal instead of near one limit.
4. Which matters more in production, precision or accuracy?
Production needs both, but they matter in different ways. Accuracy makes sure the part meets the drawing, while precision makes sure that the result can be repeated across multiple parts and batches. Without accuracy, the process makes the wrong part. Without precision, the process cannot maintain stable quality.
5. What causes poor accuracy in machined parts?
Poor accuracy usually comes from factors that shift the result away from the target value. Common causes include calibration drift, incorrect offsets, unsuitable cutting parameters, thermal expansion, material behavior, and programming errors. Even a repeatable process can still show poor accuracy when one of these factors moves the result away from nominal.
