Ball screw assemblies specified by catalog page fail at commissioning: wrong lead pitch forces rpm past critical speed, and undocumented accuracy grades cannot be verified. This solution matches lead, grade and end fixing to your axis, with C7/C5 records and zero-backlash double-nut options.
Sourcing a ball screw assembly for a CNC or automation axis is full of expensive detours. Buyers routinely order a lead pitch that looks fine on paper, then discover at commissioning that hitting the target rapid speed forces rpm above the screw's critical speed, and the screw whips. Others accept backlash they believe is inherent, only to lose bidirectional repeatability on positioning axes. And assemblies quoted without documented lead accuracy arrive with no inspection sheet to argue against.
Dongfeng supplies the assembly as an engineered system, not a bare screw. Rolled C7 (SFU) and ground C5 (SFE) screws per ISO 3408 cover cost-driven and precision axes; DFU double-nut assemblies hold axial play below 0.003 mm with precision-spacer preload; BSH miniature ground screws cover sub-12 mm shafts for lab and medical automation. Ends are machined to your fixing-unit interface, so the assembly bolts into your axis with matched support bearings.
Who / what: a router builder needed 3 m X-axis travel at 12 m/min rapid. Problem: their 5 mm lead screws needed 2,400 rpm to hit the speed target and whip became audible at the ends of travel.
Where the numbers come from: the builder's axis commissioning report, with rpm and rapid measurements recorded at machine acceptance.
Source: commissioning report shared by the builder's project engineer.
Who / what: a mold-maker retrofitting a heavy clamp plate axis. Problem: backlash from a worn trapezoidal screw ruined repositioning accuracy.
Where the numbers come from: before/after dial-indicator measurements taken by the customer's maintenance team, logged in their service sheet.
Source: customer maintenance log with dial readings from the retrofit.
★★★★★
RFQ sent through the trade platform for a router gantry retrofit program.
"Their engineer challenged my lead choice before the order, not after. The 10 mm lead version passed commissioning without touching the servo limits."
Source type: platform order review plus commissioning email from the builder.
★★★☆☆
Direct factory contract for a mold-change axis retrofit through a distributor partner.
"The double-nut assembly arrived with its own axial-play measurement. Dial check on our side matched within a micron."
Source type: annual purchase record and incoming measurement log.
★★★★★
Sample request for a semiconductor handling stage from an automation integrator.
"C5 lead-accuracy sheet matched our CMM reading at ±0.008 mm per 300 mm. That ended the grade debate in one meeting."
Source type: integrator's CMM report compared against our inspection record.
Ask for the precision-grade certificate and lead-accuracy inspection sheet with your quotation; each C5 order ships with its own measurement record.
SFU1605 rolled ball screw assembly with C7 precision grade, 5 mm lead, and pre-loaded single nut — suited for 3D printers, laser engravers, and light CNC gantry axes where cost-efficient linear motion at ±0.05 mm/300 mm positioning tolerance is sufficient.
SFU2510 rolled ball screw assembly with 25 mm shaft and 10 mm lead, delivering 17.2 kN dynamic load (2.5× the SFU1605) at C7 precision grade. Designed for mid-size CNC router X/Y axes up to 3 m travel, plasma cutting tables, and woodworking gantry machines where the SFU1605's load capacity is insufficient.
SFU3205 heavy-duty rolled ball screw with 32 mm shaft and 5 mm lead, delivering 22.5 kN dynamic load at C7 precision grade. The 32 mm diameter provides 2.5× the bending stiffness of SFU2510, making it ideal for VMC feed axes, CNC lathe Z-axis, and gantry mill applications where spindle head weight and cutting forces demand high rigidity.
DFU Series double-nut zero-backlash ball screw with precision spacer pre-load delivering <0.003 mm axial play and 1.5× the dynamic load of single-nut equivalents. Available in C7 rolled or C5 ground precision, shaft diameters 16–40 mm. Designed for bidirectional positioning axes in automation, semiconductor handling, and measurement equipment.
SFE2005 ground ball screw assembly at C5 precision grade, delivering ±0.008 mm/300 mm lead accuracy with a 20 mm shaft and 5 mm lead — designed for semiconductor wafer handling, medical imaging stages, and precision CNC applications where positional repeatability under 0.01 mm is a hard requirement.
BSH Series miniature ground ball screw with shaft diameters 6–12 mm and C5 precision grade (±0.008 mm/300 mm lead accuracy). Compact 20 mm nut envelope and 2.1 kN dynamic load at BSH0802. Designed for medical pipetting robots, lab automation, and optical positioning systems requiring sub-micron resolution in tight envelopes.
Start from your required linear speed: speed (mm/min) equals lead (mm) times rpm. A larger lead hits the same speed at lower rpm, which reduces whip and heat. Then check the nut's dynamic load against your payload and duty cycle.
C7 rolled screws hold about ±0.05 mm per 300 mm and cost less, suiting routers and general automation. C5 ground screws hold ±0.008 mm per 300 mm for positioning stages and precision machines, at a higher price and longer lead time.
Use a double-nut preloaded assembly when the axis must approach a target from both directions with zero lost motion, for example in bidirectional positioning, gear changing or measurement axes. Axial play stays under 0.003 mm.
Yes. Ends can be machined to standard fixing-unit interfaces, and matching support bearings and seats can be quoted with the screw so the assembly arrives ready to mount.
Limit rpm against the critical-speed curve for the unsupported length, choose fixed-supported or fixed-fixed end fixing, and increase shaft diameter where the speed requirement demands it - the calculator above applies these rules.
Send your axis requirements — travel, load, speed and environment — and our engineers reply with a matched specification and quotation.
