{"id":636,"date":"2026-05-29T03:35:57","date_gmt":"2026-05-29T03:35:57","guid":{"rendered":"https:\/\/planetary-gearboxes.com\/?p=636"},"modified":"2026-05-29T03:40:01","modified_gmt":"2026-05-29T03:40:01","slug":"planetary-gearbox-cnc-machine-tools-rotary-table","status":"publish","type":"post","link":"https:\/\/planetary-gearboxes.com\/bg\/planetary-gearbox-cnc-machine-tools-rotary-table\/","title":{"rendered":"\u041f\u043b\u0430\u043d\u0435\u0442\u043d\u0430 \u0441\u043a\u043e\u0440\u043e\u0441\u0442\u043d\u0430 \u043a\u0443\u0442\u0438\u044f \u0437\u0430 CNC \u043c\u0430\u0448\u0438\u043d\u0438"},"content":{"rendered":"

<\/p>\n
\"precision<\/p>\n
\n
CNC Machine Tool Application Guide \u00b7 Downtime Cost Analysis<\/div>\n

Precision Planetary Gearbox for CNC Machine Tools \u2014
\nRotary Table, B-Axis and Gantry Rack Drive<\/h1>\n

CNC machine tool axes impose the most demanding combination on a \u043f\u0440\u0435\u0446\u0438\u0437\u043d\u0430 \u043f\u043b\u0430\u043d\u0435\u0442\u0430\u0440\u043d\u0430 \u0441\u043a\u043e\u0440\u043e\u0441\u0442\u043d\u0430 \u043a\u0443\u0442\u0438\u044f<\/strong> \u2014 whether driving a rotary table, B-axis head, or rack and pinion gantry axis: sub-arcminute backlash for dimensional accuracy, high continuous torque for workpiece clamping and cutting forces, and \u2014 for rack-driven gantry axes \u2014 the ability to replace a worn pinion in 30 minutes rather than 4 hours without machine recalibration. This guide provides the engineering calculation and product selection for each CNC drive type.<\/p>\n

View Precision EP Series \u2192
\n<\/a><\/p>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Three CNC Drive Types \u2014 Three Different Gearbox Priority Specifications<\/h2>\n
\n
\n

A CNC machining centre contains three fundamentally different types of servo drive that each place different demands on the planetary gearbox. Understanding which drive type you are specifying \u2014 and its dominant performance requirement \u2014 prevents the most common Korean CNC OEM selection error: applying the same P0 specification uniformly across all axes when P0 is only necessary on two or three of them, or conversely, tolerating accumulated backlash on a B-axis tilting head by choosing a compound external bevel configuration.<\/p>\n

The three drive types and their governing specifications are:<\/p>\n

\n
\n
\u2460 Rotary Table (A\/B\/C axis rotation)<\/div>\n

Drives a workpiece-holding table through angular positioning. Backlash is the primary specification<\/strong> \u2014 it directly translates to a linear positioning error at the workpiece surface. Every arcminute of gearbox backlash produces a measurable dimensional error on the machined part proportional to the distance from the table rotation centre. This is the axis where P0 or ultra-precision specification has the greatest functional justification.<\/p>\n<\/div>\n

\n
\u2461 B-Axis \/ C-Axis Tilting Head<\/div>\n

Rotates the spindle head through a 90\u00b0 angle \u2014 motor horizontal inside the column, output driving the tilting mechanism perpendicular to the column axis. Backlash plus integrated right-angle geometry<\/strong> are the key specifications. An external bevel stage added after an inline gearbox accumulates backlash; an integrated right-angle unit measures total backlash at the output shaft. This is where the right-angle series selection from Article 3 directly applies to CNC context.<\/p>\n<\/div>\n

\n
\u2462 Gantry Rack-and-Pinion Linear Axis<\/div>\n

Drives the gantry carriage along a rack \u2014 unlimited travel, high feed rates. Pinion wear cycle and replacement downtime<\/strong> is the dominant operational concern, not backlash grade. At 120 m\/min feed rates in Korean aerospace gantry machines, the pinion (a consumable wear component) may require replacement every 4\u20136 months. The gearbox-to-pinion interface design determines whether each replacement costs 30 minutes or 4 hours of machine downtime.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

\"precision
\n<\/p>\n
\n

CNC AXIS TYPE \u2192 PRIORITY SPEC<\/p>\n

Rotary table \u2192 Backlash (P0)
\nB-axis head \u2192 R\/A integrated
\nGantry rack \u2192 Pinion replace
\nChip conveyor \u2192 Cost (Econ.)
\nTool magazine \u2192 Ratio match<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n
\n

Rotary Table Gearbox \u2014 Calculating the Backlash-to-Part-Error Relationship<\/h2>\n
\n
\n

For every planetary gearbox CNC machine tool rotary axis, the backlash specification must be derived from the part tolerance \u2014 not chosen from a catalogue default. The calculation chain is: gearbox backlash in arcminutes \u2192 angular play at the table surface \u2192 linear dimensional error at the workpiece cutting point. This chain must close within the part tolerance budget, accounting for all other sources of error in the machine.<\/p>\n

<\/p>\n

\n

BACKLASH \u2192 LINEAR PART ERROR<\/p>\n

\u0394x = r \u00d7 \u03b8_backlash (radians)
\nwhere \u03b8 (rad) = arcmin \u00d7 \u03c0 \/ (180 \u00d7 60)
\n\u03b8 for 1 arcmin = 0.000291 radiansAt r = 150 mm (workpiece edge):
\n1 arcmin \u2192 \u0394x = 150 \u00d7 0.000291 = 0.044 mm<\/span>
\n3 arcmin \u2192 \u0394x = 150 \u00d7 0.000873 = 0.131 mm<\/span>
\n5 arcmin \u2192 \u0394x = 150 \u00d7 0.001455 = 0.218 mm<\/span><\/div>\n<\/div>\n

ISO tolerance class mapping:<\/strong> For an ISO H7 bore with 50 mm diameter (tolerance \u00b10.025 mm total band), the backlash contribution from the rotary table gearbox should not exceed 30\u201340% of the total tolerance budget \u2014 leaving room for other error sources (spindle runout, thermal drift, feed axis positioning). This typically means the backlash contribution must stay below \u00b10.008 to \u00b10.010 mm \u2014 achievable only with P0 \u22641 arcmin at standard Korean CNC rotary table radii of 100\u2013200 mm.<\/p>\n

For heavy rotary tables handling large steel slabs or oversize workpieces \u2014 where clamping torque requirements exceed what the precision AFH\/AB range covers \u2014 the EP-AH New Line series<\/a> at 1\u20132 arcmin backlash covers up to 9,585 N\u00b7m output torque in frames to 450 mm body diameter. This 1\u20132 arcmin specification is adequate for heavy structural steel tolerances (IT9\u2013IT10) where the workpiece geometry itself is rougher than the gearbox backlash contribution.<\/p>\n<\/div>\n

\n

Workpiece Type \u2192 Required Backlash \u2192 Korea Ever-Power Series<\/p>\n

\n\n\n\n\n\n\n\n\n\n
Workpiece \/ Operation<\/th>\nISO Class<\/th>\n\u0417\u0430\u0434\u044a\u043b\u0436\u0438\u0442\u0435\u043b\u043d\u043e
\n\u041d\u0435\u0433\u0430\u0442\u0438\u0432\u043d\u0430 \u0440\u0435\u0430\u043a\u0446\u0438\u044f<\/th>\n		\u0421\u0435\u0440\u0438\u044f<\/th>\n<\/tr>\n<\/thead>\n
Aerospace titanium (5-axis)<\/td>\nIT6\u2013IT7<\/td>\n\u22641 \u0434\u044a\u0433\u043e\u0432\u0430 \u043c\u0438\u043d\u0443\u0442\u0430<\/td>\nEP-AFH<\/a><\/td>\n<\/tr>\n
Auto die \/ precision mould<\/td>\nIT7\u2013IT8<\/td>\n\u22641 \u0434\u044a\u0433\u043e\u0432\u0430 \u043c\u0438\u043d\u0443\u0442\u0430<\/td>\nEP-AFH<\/a> \/ EP-AB P0<\/td>\n<\/tr>\n
Aluminium automotive parts<\/td>\nIT8\u2013IT9<\/td>\n\u22643 \u0434\u044a\u0433\u043e\u0432\u0438 \u043c\u0438\u043d\u0443\u0442\u0438<\/td>\nEP-AB P1<\/a><\/td>\n<\/tr>\n
General structural steel<\/td>\nIT10\u2013IT11<\/td>\n\u22645 \u0434\u044a\u0433\u043e\u0432\u0438 \u043c\u0438\u043d\u0443\u0442\u0438<\/td>\nEP-AB P2<\/td>\n<\/tr>\n
Heavy steel slab (flip table)<\/td>\nIT9\u2013IT10<\/td>\n1\u20132 arcmin<\/td>\nEP-AH<\/a> New Line<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
\n
Why EP-AFH rather than EP-AB P0 for highest precision?<\/div>\n

EP-AFH delivers \u22641 arcmin as its standard specification without a grade code<\/em> \u2014 not as a P0 sub-selection within a range. This means every EP-AFH unit, at every ratio and every frame, is verified at \u22641 arcmin at the factory. It also reaches 3,805 N\u00b7m maximum at frame 240 mm \u2014 sufficient for Korean bridge-type machining centre rotary table clamping torques that the AB P0 series cannot address.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

B-Axis and Tilting Head Drives \u2014 Why Integrated Right-Angle Matters for CNC<\/h2>\n
\n
\n

The B-axis on a 5-axis CNC machining centre tilts the spindle head to achieve simultaneous 5-axis cutting. The servo motor is typically mounted horizontally inside the machine column; its output must drive the tilting mechanism at 90\u00b0 to the column axis. This layout demands a right-angle gearbox \u2014 and the backlash specification of that right-angle gearbox directly determines the angular positioning accuracy of the spindle head, which feeds directly into workpiece dimensional accuracy.<\/p>\n

Korean 5-axis machining centres for aerospace and automotive tooling supply specify B-axis angular positioning accuracy of \u00b10.005\u00b0 to \u00b10.010\u00b0 (0.3 to 0.6 arcmin). This means the gearbox backlash budget for the B-axis drive is \u22640.3\u20130.6 arcmin \u2014 requiring P0 or better. An external bevel pair added after an inline P0 gearbox introduces 3\u20135 arcmin additional backlash, producing a total of 4\u20136 arcmin \u2014 10\u00d7 over the specification. The 5-axis accuracy specification is simply not achievable with a compound external configuration.<\/p>\n

The EP-ABR integrated right-angle series<\/a> solves this by measuring P0\/P1\/P2 backlash at the right-angle output shaft with the bevel stage included. Confirmed Korean case: EP-ABR090 P1 i=25, five-axis machining centre B-axis tilting head. Backlash at delivery: 2.4 arcmin measured at the output shaft. 19 months continuous operation across 3 machines at an aerospace subcontractor in Siheung, zero backlash rework requests.<\/p>\n

<\/p>\n

Why P1 was specified rather than P0 for this B-axis: <\/strong>
\nThe machine’s B-axis uses a dual-drive pre-load arrangement \u2014 two EP-ABR090 units driving the same tilting axis from opposite sides with a small angular pre-load applied between them. The pre-load eliminates the effective backlash at the axis level regardless of the individual gearbox grade, making P1 at 2.4 arcmin in the individual unit deliver sub-0.5 arcmin system backlash through the pre-load compensation. Specifying P0 at 60% higher unit cost would have provided no functional improvement. This is a common engineering optimisation in 5-axis machine tool design.<\/span><\/div>\n<\/div>\n
\n
\n

B-AXIS BACKLASH CHAIN ANALYSIS<\/p>\n

External compound config:
\n[Motor]
\n\u2514\u2500[Inline P0 AB090] \u22641.0′
\n\u2514\u2500[External bevel] +3\u20135′
\n\u2514\u2500 Total: 4\u20136 arcmin \u274cIntegrated right-angle:
\n[Motor]
\n\u2514\u2500[EP-ABR090 P1] \u22643.0′ total
\n\u2514\u2500 Measured at R\/A shaft \u2713With dual pre-load:
\n2\u00d7 EP-ABR090 P1 + pre-load
\n\u2192 System backlash \u22640.5′ \u2713\u2713<\/div>\n
Pre-load compensation between dual drives is standard Korean 5-axis machining centre engineering. Individual gearbox P1 grade + pre-load \u2192 superior result vs single P0 unit at higher cost<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Gantry Rack-and-Pinion Linear Axis \u2014 Why Maintenance Cost Is the Governing Factor<\/h2>\n

Rack-and-pinion linear axis gearbox selection \u2014 with the right planetary gearbox CNC configuration \u2014 determines machine uptime as much as precision grade. Rack-and-pinion is the dominant linear drive architecture for large-format Korean CNC machining centres, laser cutting systems, and gantry structures \u2014 because a rack can be extended to unlimited travel length, and feed rates of 60\u2013150 m\/min are achievable that ballscrew drives cannot match beyond approximately 6 m travel. What rack-driven gantry architects do not always build into their total cost of ownership model is the consequence of the pinion being a wear component.<\/p>\n

\"\u0434\u0435\u0442\u0430\u0439\u043b\u0438<\/p>\n

\n
\n

The Pinion Wear Problem<\/h3>\n

In a rack-and-pinion linear drive, the pinion tooth flanks wear against the rack over millions of engagement cycles. At Korean aerospace gantry machining centres running at 120 m\/min maximum feed rate in three-shift operation, the pinion tooth flank wear reaches the replacement threshold in 4\u20136 months. This is not a product quality issue \u2014 it is an inherent tribological consequence of the rack-pinion contact geometry under high-cycle, high-force conditions.<\/p>\n

The economic question is not whether the pinion wears \u2014 it will \u2014 but how long the replacement procedure takes and whether it requires machine recalibration after each event. With a conventional spline or key-shaft connection between the gearbox output and the pinion, pinion replacement requires: disconnecting the servo motor cables, removing the gearbox from the carriage assembly, extracting the worn pinion from the spline or key connection (requiring a dedicated extraction tool), pressing the new pinion onto the connection, re-installing the gearbox, reconnecting the servo motor, and performing a machine-axis recalibration run. Total elapsed time: 2\u20134 hours per gearbox, per replacement event.<\/p>\n

On a typical Korean 5-axis gantry machining centre with two EP-AP units driving both sides of the gantry bridge, this procedure must be performed on both sides simultaneously to maintain gantry synchronisation \u2014 effectively doubling the downtime to 4\u20138 hours per maintenance event, occurring 2\u20133 times per year.<\/p>\n<\/div>\n

\n

The Curvic Plate Solution<\/h3>\n

The EP-AP\/APK Curvic Plate series<\/a> replaces the spline\/key connection with a patented curved-tooth face-gear disc (the Curvic Plate) that connects the pinion to the gearbox output shaft via a single clamping screw. The curved-tooth geometry is self-centring \u2014 when the screw is tightened, the Curvic teeth automatically force the pinion to the same centreline position regardless of installation sequence. Pinion replacement procedure: loosen one screw, slide off worn pinion, slide on new pinion, tighten one screw. No motor disconnect. No gearbox removal. No recalibration required.<\/p>\n

\n
Confirmed Korean case \u2014 12\u00d75 m aerospace gantry:<\/div>\n

EP-AP200 Curvic Plate on both X-axis sides of a 12 m \u00d7 5 m gantry machining centre. Previous spline-type gearbox: first pinion change on each side took 3.5 hours each, 7 hours total including gantry sync recalibration after both sides. With AP Curvic Plate: both sides completed in 55 minutes, no gantry sync recalibration required \u2014 Curvic Plate restored both sides to within 0.008 mm of pre-change gantry synchronisation without a calibration run.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n
\u041f\u0430\u0440\u0430\u043c\u0435\u0442\u044a\u0440<\/th>\nConventional Spline\/Key<\/th>\nCurvic Plate \u2014 EP-AP\/APK<\/th>\n<\/tr>\n<\/thead>\n
Replacement steps<\/td>\nMotor disconnect \u2192 gearbox removal \u2192 spline extraction \u2192 press-fit new \u2192 reinstall \u2192 recalibrate<\/td>\nLoosen 1 screw \u2192 swap pinion \u2192 tighten 1 screw<\/td>\n<\/tr>\n
Time per gearbox unit<\/td>\n2\u20134 hours (incl. recalibration)<\/td>\n15\u201330 minutes<\/td>\n<\/tr>\n
Recalibration required<\/td>\nYes \u2014 spline position varies each reinstallation<\/td>\nNo \u2014 Curvic self-centring restores position<\/td>\n<\/tr>\n
Motor cable disconnect<\/td>\nYes (gearbox removal required)<\/td>\nNo (pinion replaced from output side)<\/td>\n<\/tr>\n
Specialist tool required<\/td>\nYes \u2014 spline extraction press<\/td>\nNo \u2014 standard hex key<\/td>\n<\/tr>\n
Annual replacements (3-shift)<\/td>\n2\u20133<\/td>\n2\u20133<\/td>\n<\/tr>\n
Annual downtime (dual gantry)<\/td>\n14\u201324 hours baseline<\/td>\n1\u20132 hours \u2014 saving 13\u201322 h\/yr<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
Fleet-level quantification: <\/strong>
\nA Korean aerospace machining subcontractor operating 6 large gantry machines with dual-drive EP-AP200 Curvic Plate confirmed 55 minutes per full dual-side pinion replacement event, versus 7 hours for the previous spline-type gearboxes. Net saving: 6.08 hours per event \u00d7 2.5 events per year \u00d7 6 machines = 91 hours of recovered machine time per year<\/strong>. At a conservative Korean CNC machining hourly rate, this translates to significant annual productivity recovery \u2014 without changing the pinion wear rate itself, only the replacement procedure time.<\/span><\/div>\n<\/section>\n

<\/p>\n

\n

Calculating the Required Gearbox Output Torque for a Rack-and-Pinion Axis<\/h2>\n
\n
\n

Specifying the correct EP-AP frame size for a rack drive requires calculating the output torque demand from the rack system parameters \u2014 not from a generic “heavy duty” classification. The formula is straightforward and provides a precise frame size starting point.<\/p>\n

\n

RACK DRIVE TORQUE CALCULATION<\/p>\n

T_output = F_rack \u00d7 r_pinion
\nF_rack = F_cutting + F_acceleration
\nF_accel = m \u00d7 a (moving mass \u00d7 accel)Example \u2014 Korean aerospace gantry:
\nF_cutting (Inconel): 12,000 N
\nF_accel (3,000 kg, 2 m\/s\u00b2): 6,000 N
\nF_rack total: 18,000 N
\nr_pinion (m=4, Z=20): 0.040 mT_output = 18,000 \u00d7 0.040
\n= 720 N\u00b7m per side<\/span>With safety factor 1.5\u00d7 \u2192 1,080 N\u00b7m
\n\u2192 EP-AP140 covers this (to 1,400 N\u00b7m)<\/div>\n<\/div>\n

For dual-drive gantry configurations where two EP-AP units drive opposite sides of the gantry bridge simultaneously, the force calculation applies per side \u2014 each gearbox handles half the total gantry cutting and acceleration force for symmetric gantry motion, but must handle full force during single-axis lead-axis corrections and skew corrections.<\/p>\n

Korea Ever-Power provides a rack drive torque calculation worksheet in Korean on request \u2014 supply the rack module (m), pinion tooth count (Z), moving mass (kg), maximum acceleration (m\/s\u00b2), and cutting force specification, and the Korea Ever-Power application team returns the recommended EP-AP frame size with safety factor applied.<\/p>\n<\/div>\n

\n

EP-AP\/APK Frame Selection by Rack System<\/p>\n

\n\n\n\n\n\n\n\n\n\n
\u041f\u0440\u0438\u043b\u043e\u0436\u0435\u043d\u0438\u0435<\/th>\nRack Force<\/th>\nT_output<\/th>\nEP-AP Frame<\/th>\n<\/tr>\n<\/thead>\n
Fibre laser cutting (6\u00d720 m)<\/td>\n3,000\u20136,000 N<\/td>\n120\u2013240 N\u00b7m<\/td>\nAP090<\/td>\n<\/tr>\n
Plasma cutting (heavy plate)<\/td>\n5,000\u201310,000 N<\/td>\n200\u2013400 N\u00b7m<\/td>\nAP110<\/td>\n<\/tr>\n
Gantry mill (aluminium)<\/td>\n8,000\u201315,000 N<\/td>\n320\u2013600 N\u00b7m<\/td>\nAP140<\/td>\n<\/tr>\n
Gantry mill (Inconel\/titanium)<\/td>\n15,000\u201325,000 N<\/td>\n600\u20131,000 N\u00b7m<\/td>\nAP140\u2013AP200<\/td>\n<\/tr>\n
Shipyard portal crane traversal<\/td>\n80,000\u2013200,000 N<\/td>\n3,200\u20138,000 N\u00b7m<\/td>\nAP355\u2013APK450<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Basis: r_pinion = 40 mm (m=4, Z=20). Safety factor 1.5\u00d7 applied. Actual specification requires full duty cycle analysis.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Auxiliary CNC Axes \u2014 Not Every Axis Needs P0, and the Interface Still Matters<\/h2>\n
\n
\n

A 5-axis machining centre with 12 servo axes does not need twelve P0 precision gearboxes. Chip conveyor drives, coolant pump actuators, tool magazine carousel rotation, pallet shuttle drives, and door actuators are open-loop or speed-controlled axes where backlash is irrelevant to machine accuracy. Specifying P0 on these axes is a direct cost penalty with zero functional return.<\/p>\n

The Korea Ever-Power Economic Line PA II series<\/a> is specifically designed for this CNC auxiliary axis application: the PA II body diameter matches the EP-AB inline series dimension-for-dimension, so a single mechanical drawing can specify both precision EP-AB P0\/P1 on the critical axes and Economic Line PA II on the auxiliary axes, using the same motor adapter plate and mounting flange geometry throughout.<\/p>\n

The PA II’s 6\u20138 arcmin single-stage backlash is entirely adequate for chip conveyor speed control, where the only positioning requirement is “running” versus “stopped.” The significant cost differential between PA II and AB P0 at the same frame size allows a CNC OEM to allocate the precision budget to the 3\u20134 axes that actually determine machine accuracy, rather than diffusing it across all 12.<\/p>\n<\/div>\n

\n

<\/p>\n

\n
CNC Axis Tiering \u2014 Precision vs Economic<\/div>\n
\n
\n
PRECISION TIER (EP-AFH \/ EP-AB P0)<\/div>\n
Rotary table (A\/B\/C axis) \u00b7 5-axis tilting head \u00b7 High-speed spindle head \u00b7 Indexing axis<\/div>\n<\/div>\n
\n
MID TIER (EP-AB P1\/P2 \u00b7 EP-ABR P1)<\/div>\n
General servo positioner \u00b7 B-axis (with pre-load) \u00b7 Pallet shuttle linear axis \u00b7 ATC carousel drive<\/div>\n<\/div>\n
\n
ECONOMIC TIER (PA II \/ PE II)<\/div>\n
Chip conveyor \u00b7 Coolant pump actuator \u00b7 Door \/ guard drive \u00b7 Lubrication distribution \u00b7 Fixture clamp<\/div>\n<\/div>\n<\/div>\n

PA II and EP-AB share the same motor adapter plate size \u2014 a single mechanical design supports all three tiers on the same machine.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

\"planetary<\/p>\n

\n

Tool Magazine and Indexer Drives \u2014 Round Flange and Non-Standard Ratios<\/h2>\n
\n
\n

CNC machining centre tool magazines, Hirth coupling indexers, and rotary pallet tables frequently require non-standard reduction ratios \u2014 the number of tools in a magazine carousel (typically 20, 30, or 40 positions) must match the motor revolution count per tool change without a variable-frequency drive, using only the gear ratio to produce the correct angular increment per motor step command.<\/p>\n

Standard planetary series cover ratios of 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25… the set available depends on the series. For a 30-tool magazine where the tool-change servo must advance exactly 12\u00b0 (360\u00b0\/30) per tool position \u2014 requiring an exact integer number of motor revolutions per 12\u00b0 tool increment \u2014 the ratio needed may be 21:1, 31:1, or 61:1, which are not available in the standard AB series.<\/p>\n

The EP-AD round flange series<\/a> and its compact variant EP-ADS<\/a> offer the non-standard ratios 16, 21, 31, 61, and 91 in addition to the standard series \u2014 enabling exact tool magazine indexing without a VFD. The round flange also self-centres on the magazine housing bore, simplifying indexer alignment.<\/p>\n<\/div>\n

\n

\"\u0412\u0438\u0441\u043e\u043a\u043e\u043f\u0440\u0435\u0446\u0438\u0437\u043d\u0430<\/p>\n

\n
Non-standard ratio availability \u2014 AD\/ADS series<\/div>\n
Standard: 4\/5\/7\/10\/12\/15\/20\/25…
\nNon-std: 16 \/ 21 \/ 31 \/ 61 \/ 9130-tool mag (12\u00b0 per step):
\nMotor 1,500 rpm, 0.5s per step
\n\u2192 Need i=21 exactly \u2192 ADS available<\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Korea Ever-Power CNC Machine Tool Selection \u2014 Complete Quick Reference<\/h2>\n

The table below consolidates the selection logic from all modules \u2014 covering rotary table, B-axis, rack and pinion gantry, auxiliary, and indexer axes into a single CNC application reference. Use it as a starting point \u2014 always verify with the full torque calculation and backlash-to-part-tolerance analysis for your specific workpiece and cutting parameters.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
CNC Application<\/th>\n\u041a\u043e\u0440\u0435\u044f Ever-Power Series<\/th>\nKey Spec<\/th>\nSelection Reason<\/th>\n<\/tr>\n<\/thead>\n
Rotary table \u2014 titanium\/mould (precision)<\/td>\nEP-AFH 100\u2013180<\/a><\/td>\nStd \u22641′ \u00b7 3,805 N\u00b7m<\/td>\n\u22641 arcmin standard across all frames and ratios \u2014 no grade selection required<\/td>\n<\/tr>\n
Rotary table \u2014 heavy steel slab<\/td>\nEP-AH 355\/450<\/a><\/td>\n1\u20132′ \u00b7 9,585 N\u00b7m<\/td>\nHighest torque in Korea Ever-Power range for very large heavy rotary tables<\/td>\n<\/tr>\n
B-axis tilting head (5-axis)<\/td>\nEP-ABR 090 P1<\/a><\/td>\n\u22643′ total R\/A<\/td>\nBevel stage included in P1 specification \u2014 no external bevel needed<\/td>\n<\/tr>\n
Gantry rack linear axis<\/td>\nEP-AP\/APK \u0438\u0437\u0432\u0438\u0442\u0430 \u043f\u043b\u043e\u0447\u0430<\/a><\/td>\n1-screw pinion \u00b7 14,010 N\u00b7m<\/td>\nPinion replacement in 30 min vs 4 h \u2014 self-centring, no recalibration<\/td>\n<\/tr>\n
Auxiliary axes (chip conveyor, door, pallet)<\/td>\n\u0418\u043a\u043e\u043d\u043e\u043c\u0438\u0447\u0435\u0441\u043a\u0430 \u043b\u0438\u043d\u0438\u044f PA II<\/a><\/td>\n6\u20138′ \u00b7 same mount<\/td>\nIdentical flange to EP-AB \u2014 single mechanical drawing serves precision and economic tiers<\/td>\n<\/tr>\n
Tool magazine \/ indexer<\/td>\nEP-AD \/ EP-ADS<\/a><\/td>\ni=21\/31\/61\/91<\/td>\nNon-standard ratios for exact tool-position indexing without VFD<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Frequently Asked Questions \u2014 Planetary Gearbox for CNC Machine Tools<\/h2>\n
\n
\n

\u0412<\/span>
\nMy CNC rotary table drifts after every direction reversal. What is the likely cause?<\/h3>\n

Post-reversal drift on a CNC rotary table is almost always a backlash symptom. When the servo command reverses direction, the motor must first rotate through the gearbox backlash angle before the table begins to move \u2014 but the encoder continues tracking motor rotation during this lost motion, meaning the servo control loop builds up a following error that then overshoots when the table finally begins to respond. If the drift magnitude is consistent (same error at every reversal) and small (sub-millimetre at the workpiece edge), measure the table output backlash directly with a dial indicator: lock the table clamp, rotate the input through a small angle, and measure angular play at the table face. Compare this to the gearbox specification. If backlash has grown significantly beyond the original specification, the gearbox requires replacement. If it is within specification, the drift is likely servo tuning \u2014 increase derivative gain (D) to suppress the following error spike at reversal.<\/p>\n<\/div>\n

\n

\u0412<\/span>
\nHow often does a Korean gantry machine rack-drive pinion need replacement under 3-shift operation?<\/h3>\n

The replacement interval depends on feed rate, material hardness, lubrication system quality, and rack surface hardness. At Korean aerospace gantry machining centres running at 80\u2013120 m\/min rapid traverse with Inconel and titanium cutting, pinion tooth flank wear reaches the replacement threshold in 4\u20136 months. Fibre laser cutting systems at 120 m\/min positioning speed (not cutting speed) with a properly lubricated rack see 8\u201312 month pinion intervals. Plasma cutting gantries at lower positioning speeds may achieve 12\u201318 months. These intervals are not improved by upgrading the gearbox \u2014 only by improving rack and pinion lubrication frequency and quality, or by reducing the feed rate during the wear-sensitive cutting passes.<\/p>\n<\/div>\n

\n

\u0412<\/span>
\nCan I use a New Line EP-AH gearbox as a direct replacement for an EP-AFH on a precision rotary table?<\/h3>\n

The EP-AH New Line delivers 1\u20132 arcmin backlash \u2014 in many frame sizes this is comparable to or better than EP-AFH \u22641 arcmin when tolerance stack-up in the table mechanism is considered. For heavy rotary tables where AH’s higher torque is needed, this is the correct substitution. However, the mounting flange geometry of AH\/AHK differs from AFH \u2014 AH uses a larger, heavier frame scale designed for structural industrial installation rather than machine tool adapter plate mounting. A direct drop-in replacement requires verifying the mounting interface dimensions match. Korea Ever-Power application team can confirm the dimensional compatibility for your specific table housing and motor configuration.<\/p>\n<\/div>\n

\n

\u0412<\/span>
\nFor dual-drive gantry synchronisation, should both EP-AP units be the same frame size, and can CV shafts be used?<\/h3>\n

Yes \u2014 in a standard bilateral dual-drive gantry (two servo motors, one on each side), both EP-AP units must be the same frame size and the same ratio to maintain gantry synchronisation accuracy. Any frame size mismatch produces different output speeds at the same input speed, which the gantry synchronisation control loop must compensate through constant torque correction \u2014 increasing heat and wear on both units. For asymmetric gantry configurations or offset motor placements where the servo motor cannot be positioned coaxially with the rack axis, precision CV drive shafts<\/a> transmit the gearbox output torque through an angular offset to the pinion position \u2014 maintaining synchronisation torque transfer without adding additional backlash or misalignment error to the rack mesh.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Engineering Support for Your CNC Gearbox Specification<\/h2>\n

Korea Ever-Power provides backlash-to-part-tolerance calculation, rack drive torque analysis, Curvic Plate pinion module compatibility confirmation, and CNC axis tiering recommendations \u2014 in Korean, same working day. Provide your workpiece tolerance class, cutting forces, and drive type to receive a direct product recommendation.<\/p>\n

EP-AFH Precision Rotary Table \u2192
\n<\/a>
\nEP-AP Curvic Plate Rack Drive \u2192
\n<\/a><\/div>\n<\/section>\n

\u0420\u0435\u0434\u0430\u043a\u0442\u043e\u0440: Cxm
\n<\/main><\/p>","protected":false},"excerpt":{"rendered":"

CNC Machine Tool Application Guide \u00b7 Downtime Cost Analysis Precision Planetary Gearbox for CNC Machine Tools \u2014 Rotary Table, B-Axis and Gantry Rack Drive CNC machine tool axes impose the most demanding combination on a precision planetary gearbox \u2014 whether driving a rotary table, B-axis head, or rack and pinion gantry axis: sub-arcminute backlash for […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[965],"tags":[],"class_list":["post-636","post","type-post","status-publish","format-standard","hentry","category-application-and-technical-guid"],"_links":{"self":[{"href":"https:\/\/planetary-gearboxes.com\/bg\/wp-json\/wp\/v2\/posts\/636","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/planetary-gearboxes.com\/bg\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/planetary-gearboxes.com\/bg\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/bg\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/bg\/wp-json\/wp\/v2\/comments?post=636"}],"version-history":[{"count":5,"href":"https:\/\/planetary-gearboxes.com\/bg\/wp-json\/wp\/v2\/posts\/636\/revisions"}],"predecessor-version":[{"id":641,"href":"https:\/\/planetary-gearboxes.com\/bg\/wp-json\/wp\/v2\/posts\/636\/revisions\/641"}],"wp:attachment":[{"href":"https:\/\/planetary-gearboxes.com\/bg\/wp-json\/wp\/v2\/media?parent=636"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/bg\/wp-json\/wp\/v2\/categories?post=636"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/bg\/wp-json\/wp\/v2\/tags?post=636"}],"curies":[{"name":"\u0440\u0430\u0431\u043e\u0442\u043d\u0430 \u0441\u0440\u0435\u0449\u0430","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}