Eight out of ten valve sleeve leaks are not O-ring quality problems but groove and bore problems.

• Groove width and spacing consistency — each groove ±0.02 mm wide with ±0.03 mm spacing, so every O-ring sits in its designed compression range instead of one tight and one loose.
• Groove bottom radius and roughness — groove bottom R0.2, Ra 1.6, so the O-ring is not sheared by a sharp edge in reciprocating motion, which is the most common root cause of early leaks.
• Honing after heat treatment — 40Cr quenched and tempered to HRC 28-32 shrinks the bore by 0.01-0.03 mm, so bore allowance, heat treatment and honing run in sequence to hold roundness at 0.005 mm.
• Deburring of internal cross holes — radial oil holes break into the bore with a back-chamfer tool, so burrs never reach the mating surface.

Cartridge valve bore and groove standards differ between makers; we machine to drawing or reverse engineer from a sample.

• Groove Profile Customization — groove width, count, spacing and bottom radius designed around O-ring size and compression ratio.
• Material and Heat Treatment — 40Cr, 42CrMo, carburized 20CrMnTi or stainless steel, selected by pressure and media.
• Bore Process — honing, roller burnishing or boring selected by roughness and cost targets.
• Quantity — one sample for assembly validation, volume from 100 pieces, up to 20,000 pieces per batch.

Valve parts are often a customer's product under development, so confidentiality is a baseline, not a bonus. We isolate and authorize access on a per-project basis.

• NDA First — mutual NDA and non-circumvention agreement available before drawings are shared.
• Isolated Secure Area — dedicated machines and limited staff; no photography or phones inside the area.
• Not displayed — customer drawings, spool photos and pairing marks never enter sample cabinets, catalogs, the website or social media.
• Data Isolation — programs and drawings stored per project on an access-controlled server, destroyed after delivery with a destruction record.
• Code Management — traveler cards and labels use internal codes, with pairing numbering rules defined by the customer.

Dongguan Changxinda Precision Technology Co., Ltd.Founded in 2008, with a team of 90-102 staff, having served 200+ Customers, export share 50-60%, annual sales of USD 10-20 million, ISO 9001:2015 certified.

For rotational parts such as sleeves and spools, precision comes from the turning system rather than any single operation: machine thermal stability, tool holder runout and clamping distortion all show up directly in roundness. We keep turning, honing, mating lapping and inspection on one site so the dimensional chain closes internally.

• Reserved Capacity — machine time is locked weekly for volume programs, so rush orders never displace batch schedules.
• Two shifts, six days a week — production runs 07:30-22:00, with weekend shifts added in peak season.
• Buffer Stock — semi-finished stock is held for repeat specifications, cutting repeat order lead time by about 30%.
• Visible Progress — weekly progress sheet and shop floor photos, tracking number provided at shipment.
• Shipping — samples by express in 3-5 days, volume by air or sea, EXW / FOB Shenzhen / CIF.