Servo feeding ยท Timing & selection
Servo Feeder Feed-Time Calculation
Connect feed length, press angle and available timeโfor stamping and shearing lines. Calculate the demand, understand the motion, and bring the right information into equipment selection.
Calculate your feed window โ
A feeder can have a high maximum speed and still miss a short production window. The useful question is: can the complete feed move and required control response fit between the confirmed movement boundaries?
This guide starts with that window, then explains why acceleration, positioning, material flow and the press or shear sequence still need checking before a machine is selected.
How much time is available?
Change the example inputs below
Use a confirmed usable angleโnot just the feed-signal ON duration.
Available window
Required window-average speed
m/minAverage demand onlyโnot peak speed or an HMI speed setting.
Check the inputs: SPM 1โ3,000; angle 1โ360ยฐ; measured time 1โ60,000 ms; feed length 0.01โ100,000 mm. These are calculator input limits, not machine ratings.
Formula and calculation assumptions
Window time (s) = 60 รท SPM ร usable angle รท 360Average speed (m/min) = 0.06 ร feed length (mm) รท window time (s)The angle calculation assumes one revolution per stroke and uniform angular speed. For variable-speed or dwell motion, use measured time. No control delay, settling time or reserve is subtracted here. Actual motion and required non-overlapping allowances must fit the available window. The result is a demand calculation, not approval of a model or production speed.
Worked example: At 90 SPM, one cycle takes 0.667 seconds. A confirmed 180ยฐ window provides 0.333 seconds. Feeding 100 mm in that interval requires an average of 18 m/min. That average includes the entire windowโnot just the fastest part of the move.
What changes the demand?
Change one input at a time. These comparisons assume each stated angle has already been confirmed for the application; a larger angle is not a recommendation to change the cam.
| Example inputs | Available time | Average demand | Try it |
|---|---|---|---|
| Baseline90 SPM ยท 180ยฐ ยท 100 mm | 333.3 ms | 18.0 m/min | |
| Faster press120 SPM ยท 180ยฐ ยท 100 mm | 250.0 ms | 24.0 m/min | |
| Longer feed90 SPM ยท 180ยฐ ยท 200 mm | 333.3 ms | 36.0 m/min | |
| Larger confirmed window90 SPM ยท 240ยฐ ยท 100 mm | 444.4 ms | 13.5 m/min |
Faster press speed reduces time; longer feed increases travel demand. The table does not include machine-specific motion or response data.
Use the result alongside material width, thickness and the actual feed profile when comparing NC servo feeder configurations.
First define what the input means
Where does the usable feed window come from?
Start with the actual press, die and control sequence. The opening must permit the intended stock movement, and the feed must finish before the next operation requires the strip to be located and held. Pilots, lifters, formed features, release response and tool-protection logic can constrain those boundaries.
The feed request is a command; it is not proof that the strip moved for the entire time the signal was ON. Response before movement, the motion itself, position confirmation and communication with the press may occupy different intervals.
Record the start and finish definitions with the window value. Review motion and necessary allowances on one timeline; do not add overlapping delays twice or subtract an allowance already excluded from a measured window.
When the window crosses 0ยฐ
For a confirmed forward rotation, a hypothetical start at 270ยฐ and finish at 90ยฐ spans (360 โ 270) + 90 = 180ยฐ. Enter the forward span, not the numerical difference โ180ยฐ. This is angle arithmetic, not a recommended start or stop setting.
If the start and finish indicate the same angular position, confirm whether the intended span is zero or a complete revolution; do not infer a 360ยฐ window from matching angles.
From average demand to the motion profile
Why average speed is not peak speed.
A stopped strip cannot instantly reach the selected travel speed. It accelerates, may run at a steady speed, and decelerates. A short move can begin decelerating before the configured maximum is reached.
The trapezoid includes a constant-speed section. Its peak is above the move average because acceleration and deceleration also consume time.
If all available time were movement time, its required average would be the calculator result. When response, settling or reserve occupy part of the window, the movement has less time and needs a higher average. Peak demand also depends on the actual acceleration, deceleration and jerk-limited profile.
Use controller data or a verified motion record to evaluate that profile. A generic maximum-speed rating cannot establish whether the complete move will fit under the actual strip load, roll traction and process resistance.
Read HMI values in their own units
SPM means press cycles per minute. m/min means strip travel speed. Motor speed or speed % is a controller setting that needs the specified transmission and scaling. A percentage cannot be converted directly to material m/min without that information.
Likewise, a ramp-time field in milliseconds is not an acceleration in m/sยฒ. Its meaning depends on the controllerโs reference speed and profile definition. A โcutting timeโ field may specify an output-pulse duration, not the full shear cycle. Confirm the manual version for the installed machine.
Read a capacity curve before using its numbers
Check both axes: a feed-length versus SPM chart is different from a speed curve. Then identify the model, usable angle, material range, load and control settings behind it. A larger confirmed window can reduce timing demand, but an unlabeled historical curve is not a capacity guarantee for another feeder or installation.
Connect the calculation to the line
Stamping and shearing use different sequences.
Press-triggered stamping
The press or line control requests feeding within the toolโs permitted interval. Review delivered feed, completion feedback, pilot release and press permissives together. A correctly programmed feed length alone does not verify the sequence.
Feeder-triggered shearing
The sequence may run from feed and position confirmation to cut request and return-ready feedback. Check the actual handshake and shear response. Use measured time when a constant-speed press angle is not the governing reference.
These are common arrangements, not a universal wiring scheme. Document which controller owns each transition and what confirms the next operation may proceed. A pulse ending does not necessarily mean the blade has returned or that the next feed is permitted.
For shear-line details, see the NC servo feeder integration guide for shearing machines and the feeder-and-shear sequence guide.
When the result looks tight, investigate in this order
- Confirm the window definition.Check the actual cycle, start and finish conditions, and whether press speed varies. A wrong input cannot be corrected by choosing a faster feeder.
- Compare command, motion and feedback.Identify where time is consumed using approved control diagnostics. Separate the request, actual travel, position confirmation and required response.
- Review the material path and load.Include loop behavior, upstream resistance, stock support, alignment, slip and die-entry resistance. Record when the symptom appears rather than assuming the drive is the only constraint.
- Recheck the application at its intended condition.Use the approved trial procedure, representative material and quality criteria. A successful slow feed does not demonstrate stable operation at production rate.
Do not extend a feed angle, defeat an interlock or reach into the tooling to make a calculated result fit. Hands-on work requires qualified personnel and the machineโs safeguarding and energy-control procedures. The installation photographs show equipment relationships, not instructions for performing setup or service.
Equipment for your feed sequence
Turn the timing requirement into a feeder specification.
Begin with the material and movement requirement, then compare the mechanical range, drive capability, release method and control interfaces. Ask for data for the exact configuration, not just a headline speed.
The calculation helps define the demand. HENLI can review the coil-feed arrangement and identify the configuration and application information needed for selection.
Explore NC servo feeders โFrom enquiry to an accepted process
Keep a small, useful project record.
Send the inputs with their references. A reviewer needs to know not only the numbers but also the material, machine and timing definitions behind them.
| You provide | Confirm during selection | Record during acceptance |
|---|---|---|
| Material grade, thickness, width, surface requirements and feed length | Applicable material range, traction and movement profile | Material lot, delivered feed and agreed dimensional results |
| Target SPM or measured cycle, usable window and its boundary definitions | Available movement time and required non-overlapping allowances | Actual operating condition and motion/response evidence |
| Press or shear model, controller details and interface signals | Sequence ownership, completion feedback and protection requirements | Function checks and responsible release approval |
| Coil preparation, loop or tension arrangement, pass line and die-entry details | Material support, upstream capacity and installation compatibility | Stable feeding, material condition and repeatable part quality |
Define the measurement and sampling plan before the trial. Keep the approved settings, representative samples and any open limitations with the project record. Operating speed should be released against that evidenceโnot against an average-speed calculation alone.
Have a feed-time or line-speed target?
Send your material, feed length, press or shear details, intended rate and available window. Include the timing definitions and photographs of the feed path.
Discuss your feeding application โCommon feed-time questions
Can I calculate maximum press SPM from feeder speed alone?
No. A peak rating omits acceleration, deceleration and the control sequence. Matching requires the actual move profile, material load and permitted time.
Is the calculated m/min value the speed I should enter on the HMI?
Not automatically. The output is window-average strip-speed demand. An HMI may use motor speed or a percentage; interpret its setting from the exact controllerโs scaling and manual.
Does a larger feed angle always solve a timing problem?
No. It provides more calculated time only when the tool and controls genuinely permit movement for that interval. Do not enlarge the window solely to make the numbers fit.
What if the press changes speed or dwells within a stroke?
Use time measured between the confirmed movement boundaries. The angle-fraction formula assumes uniform angular speed and can misrepresent a variable-speed cycle.
Why can a short feed fail to reach the maximum speed?
The move may use all its distance accelerating and decelerating. There may be no constant-speed segment; the actual profile depends on the controller and load.
Does the calculator include cutting, settling or pneumatic response?
No. It calculates the stated window and average travel demand. Review other required intervals separately on the actual sequence, accounting for overlap and avoiding double-counting.
Technical references
- Performance Motion Devices: Mathematics of Motion Control Profiles โ acceleration, deceleration and point-to-point motion.
- COE Press Equipment: The Science Behind Servo Feeds โ feed length, angle, press speed and application demands.
Model-specific settings and acceptance limits should come from the applicable equipment documentation and project verification.
