Quality Assurance

Deliver quality parts that meet requirements and exceed expectations.

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GUAN SHENG manufacturing standards
cnc machining machine

Tighter tolerance are examined on a case by case basis with your technical drawings. Contact with info@xmgsgroup.com for special requirements.

GUAN SHENG, provides high tolerance CNC machining processes including 3, 4, 5 axis CNC milling, CNC turning, and post-processing services for your diverse manufacturing requirements.

Type Tolerance
Linear dimension +/- 0.025 mm

+/- 0.001 inch

Hole diameters

(not reamed)

+/- 0.025 mm

+/- 0.001 inch

Shaft diameters +/- 0.025 mm

+/- 0.001 inch

Smallest thread size available M1x0,25
Part size limit 950 * 550 * 480 mm

37.0 * 21.5 * 18.5 inch

If no 2D drawing is provided, GUAN SHENG produces parts according to ISO 2768 M standard. With 2D drawing, we can reach tolerance as tight as +/- 0.01 mm.


At GUAN SHENG, we offer various injection molding services which includes rapid tooling, family molds, multi-cavity molds, over molding, etc., for your manufacturing needs. Each service is based on various manufacturing standards highlighted below:

Part size (mm) Production tooling Rapid tooling
1~22 ±0.06~0.09 ±0.08~0.13
22~70 ±0.11~0.17 ±0.14~0.24
70~160 ±0.20~0.29 ±0.30~0.43
160~250 ±0.36~0.44 ±0.51~0.68
250~315 ±0.44~0.55 ±0.68~0.85
315~500 ±0.70~0.90 ±1.08~1.38
500~1000 ±1.20~1.90 ±1.83~2.90
1000~1400 ±2.30~2.65 ±3.50~4.05
1400~2000 ±3.05~3.80 ±4.65~5.80


We have experience and the right sheet metal fabrication services necessary to bring that YOUR idea to life. This includes services like high tolerance and wide thickness range laser cutting, bending capabilities, and other post-processing options.

Dimension detail Tolerance
Edge to edge, single surface +/- 0.005 inch
Edge to hole, single surface +/- 0.005 inch
Hole to hole, single surface +/- 0.005 inch
Bend to edge / hole, single surface +/- 0.010 inch
Edge to feature, multiple surface +/- 0.030 inch
Over formed part, multiple surface +/- 0.030 inch
Bend angle +/- 1°

By default, sharp edges will be broken and deburred. For any critical edges that must be left sharp, please note and specify in your drawing.


3D Printing is the best service if you want the best functional parts prototyping. At GUAN SHENG, we provide you with the best technologies in 3D printing such as FDM, SLA, SLS, Polyjet. For other technologies associated kindly contact us.

Process Min. wall thickness Layer height Max. build size Tolerance
SLA 1.0 mm 50 – 100 μm 250 * 250 * 250 mm ± 0.5% with a lower limit of ± 0.5 mm (± 0.020″)
SLS 1.0 mm 100 μm 420 * 500 * 420 mm ± 0.5% with a lower limit of ± 0.15 mm (± 0.006″)
FDM 1.0 mm 100 – 300 μm 500 * 500 * 500 mm ± 0.3% with a lower limit of ± 0.3 mm (± 0.012″)

Quality control process

Learn the most stringent inspection methods we applies over the course of the entire manufacturing process.


Technical assessment

Before the production stage begins, our engineering team performs a technical assessment on your parts design. This includes an assessment on important factors such as material, surface finish, structure, process, and other details of your 3D and 2D drawings.

Material verification

On our customer’s request, we provide a certification of the material we used for making your parts. The report comes from the raw material manufacturer and usually includes: material heat number, material grade, material dimensions, mechanical properties, chemical analysis, etc.

technical assessment
in process quality control

In production

On-site inspection system

In precision machining, it is important that materials being worked on is always at the right position. With on-site inspection system, positions are examined automatically, and adjustments are made accordingly. Using on-site inspection system further helps avoids issues at the early stage, saving cost and time.

In-process quality control

At GUAN SHENG, we strictly obey the ISO9001:2015 requirements. The quality control staff conducts routine inspections for all parts that are being produced every 2 hours. This further prevents risks from happening.

Before delivery inspection

Full-dimensional inspection report

For all orders, we provide on request. This report will include the following: quantity of parts, critical dimensions, threads and tolerances, thicknesses and depths, part appearance, etc.


Ensuring that the parts we manufacture are of the highest quality is important. We know about the unpredictability of logistics. Therefore, we make sure we lower the risk to the parts during our packaging process. Four layers of protection: 1. wrapping paper 2. EPE 3. foam 4. paper/wooden box are applied during the packaging process, ensuring that we deliver the most high-quality and beautiful parts to you.

full dimensional report

In-house inspection equipment

cmm machine

We use the Coordinate Measuring Machine (CMM) for dimensional inspection of parts produced. CMMs can measure physical parts of an object by sensing and collecting points along its surface using a probe. It is especially suitable for parts with complex geometries.

On completing the manufacturing process, we use optical comparator/ a projector to inspect the dimension of the components. This projector is ideal for dimensional check as it precisely measures the part’s dimensions and compare them to the original CAD model. Any inconsistencies detected by the projector are alerted in a detailed inspection report.

We employ X-Ray Fluorescence (XRF) analysis for checking the material quality. The XRF analyzer uses short X-rays and gamma rays to determine the elemental composition of metals, plastics and other materials, to inspect the quality of the materials.

Quality reports

For every order on our platform, we can provide a full list of quality reports according to customers’ request. Including but not limited to:

  • Inspection report
  • Full dimensional report
  • Material test report


As a decade-experience on-demand manufacturing company, we provide most commonly needed certifications, including but not limited to:

  • ISO 9001:2015
  • ROHS

First article inspection

For low-volume injection molding and CNC machining orders exceed 50 units or 5000 USD in total price, first article inspection is available on request. The process goes like below:

  • The customer request first article inspection for a project that meets our FAI requirements.
  • GUAN SHENG reviews on the project and contacts customer for detail information.
  • The customer signs the FAI agreement provided by GUAN SHENG and agree on our Terms and Conditions.
  • GUAN SHENG produce sample parts according to FAI agreement and deliver to the customer.
  • The customer receives and examines the parts, inform GUAN SHENG if full-scale production may begin.
  • The full-scale production starts and finishes production within lead time.

Resolving Quality Issues

At GUAN SHENG, it is our aim to deliver high quality parts that matches your requirements and expectations. However, if your order fails to meet your specifications, you will be covered with our Rework and Refund Policy.
Kindly get in touch with us within five business days of receiving your order, and we will resolve the problem rapidly within 1-3 business days.

Conditions for Rework

  • Unacceptable processing defects
  • Fail to meet tolerance requirement
  • Incorrect material / finish

Conditions for Refund

  • The part is not machinable
  • The customer does not agree to rework
  • Other reasons

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