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Precision CNC Machining for Complex Custom Metal Parts
From complex prototypes to reliable repeat production, Sundi MFG provides integrated CNC milling, turning, EDM, and precision grinding. We deliver tight-tolerance components for machinery, mold tooling, automation, and industrial equipment.
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No Minimum Order
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In-house CNC, EDM & Grinding
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Tolerances: ±0.005mm (CNC) / ±0.002mm (Grinding)
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Strict Quality Control
- Quote in 8h
- 7-15 Days Lead Time
- STEP / DXF / IGES Accepted
- Strictly Confidential (NDA Supported)
Machining Complex Parts Demands More Than Just Equipment
Many custom parts look simple on a 2D drawing, but become challenging on the machine floor because of tight tolerances, deep pockets, thin walls, hard materials, or sharp internal corners.
At Sundi MFG, we don’t just run machines — we review the part structure, machining risks, tolerance requirements, and finishing needs before production starts.
For complex components, we can combine CNC machining, Wire EDM, Sinker EDM, and Precision Grinding to achieve tighter dimensional control and consistent surface finishes.
CNC Machining Capabilities
At Sundi MFG, we combine CNC turning, 5-axis machining, EDM, and precision grinding to support complex custom parts from prototype to repeat production. Each project is reviewed by our engineering team to choose the right process route, control key tolerances, and reduce machining risks before production starts.
CNC Milling Service
Precision 3- and 4-axis CNC milling for complex shapes. Delivering strict tolerances for custom fixtures and structural components.
CNC Turning Service
Precision turning for cylindrical parts. Delivering exceptional concentricity and superior finishes for shafts, pins, and custom fittings.
5-Axis CNC Machining Service
Advanced 5-axis CNC machining for intricate geometries. Achieving maximum accuracy and reduced lead times with a single setup.
Grinding Service
Integrating surface, cylindrical, optical profile (PG), and 5-axis grinding. Expertly machining intricate profiles and ultra-hard materials.
EDM & Wire-Cut Service
Precision Wire and Sinker EDM for hardened alloys. Perfect for deep slots, sharp corners, and complex mold components.
CNC Drilling Services
High-precision drilling and tapping for various metals. Ensuring exact positional accuracy and flawless threads for mechanical assemblies.
Swiss CNC machining Service
Advanced Swiss turning for miniature, slender components. Delivering extreme precision and superior surface finishes in a single operation.
Micro Machining Service
Specialized micro-milling and turning for extremely small parts. Ideal for medical devices, electronics, and high-tolerance miniature components.
CNC Machining Materials
Material selection directly impacts machining strategy, tolerance stability, and final costs. Our engineering team supports a wide range of conductive and machinable materials, including Aluminum, Stainless Steel, Tool Steels, and Titanium. We review your drawings to suggest the most optimal and cost-effective machining process based on your part’s structure and intended application.
Aluminum
At Sundi MFG, we expertly machine grades like 6061, 7075, and 5083, delivering precision parts for aerospace, automotive, and electronic enclosures.
Brass
At Sundi MFG, we precision-machine grades like C360 and C260, crafting tight-tolerance gears, valves, and custom fittings for plumbing and electrical applications.
Copper
At Sundi MFG, we process pure copper grades like C101 and C110, manufacturing complex heat sinks, electrical contacts, and specialized power distribution components.
Steel
At Sundi MFG, we precisely machine grades like 1018, 4140, and 4340, producing rugged gears, shafts, and robust brackets for industrial machinery and automotive sectors.
Stainless Steel
At Sundi MFG, we expertly mill and turn 304, 316L, and 17-4PH, supplying ultra-precise components for medical devices, food processing, and marine applications.
Bronze
At Sundi MFG, we machine tough alloys like phosphor and aluminum bronze, manufacturing durable bearings, bushings, and marine hardware that require extreme wear resistance.
Titanium
At Sundi MFG, we utilize advanced tooling to machine Grade 2 and Ti-6Al-4V, delivering high-tolerance components for aerospace, medical implants, and high-performance racing.
Magnesium
At Sundi MFG, we safely and precisely process grades like AZ31B, creating ultra-lightweight, rigid components tailored for aerospace, automotive racing, and high-end electronic device housings.
Zinc
At Sundi MFG, we precisely machine custom zinc components like housings, specialized brackets, and complex mechanical linkages with extremely strict tolerances.
Inconel
At Sundi MFG, we leverage EDM and rigid CNC setups to process difficult grades like 718 and 625 for jet engines and energy sector components.
Invar
At Sundi MFG, we meticulously machine Invar 36 to produce critical components for optical instruments, laser systems, and aerospace measuring devices.
ABS
At Sundi MFG, we efficiently mill and turn custom ABS components, producing durable electronic enclosures, automotive interior parts, and rigid structural housings.
Acrylic (PMMA)
At Sundi MFG, we utilize specialized cutting tools to machine and polish Acrylic, delivering flawless display lenses, light guides, and precision microfluidic devices.
Delrin (POM)
At Sundi MFG, we precision-machine this highly stable polymer to craft tight-tolerance gears, wear-resistant bearings, and custom bushings for complex industrial assemblies.
FR4
At Sundi MFG, we safely and precisely route FR4 material, manufacturing critical PCB substrates, specialized electrical barriers, and robust structural insulators for electronics.
Nylon(PA)
At Sundi MFG, we machine various Nylon grades to produce durable mechanical components, including heavy-duty rollers, friction pads, and custom industrial gears.
PC
At Sundi MFG, we machine tight-tolerance PC components, creating rugged protective covers, transparent manifolds, and structural housings for medical and industrial equipment.
PE
At Sundi MFG, we effectively process tough PE materials, manufacturing low-friction guide rails, food-safe processing components, and reliable chemical storage fittings.
PEEK
At Sundi MFG, we apply strict environmental controls to machine PEEK, delivering ultra-precise components for aerospace, medical implants, and oil and gas applications.
PEI
At Sundi MFG, we precisely mill and turn PEI, producing critical analytical instrumentation parts, aerospace interior components, and high-performance medical device housings.
PET
At Sundi MFG, we expertly machine PET for complex applications, crafting precision fluid manifolds, food processing machinery parts, and tight-tolerance custom bearings.
PP
At Sundi MFG, we machine custom PP components for specialized industrial uses, creating robust fluid handling parts, chemical-resistant fittings, and flexible living hinges.
PTFE
At Sundi MFG, we use extremely sharp tooling to machine soft PTFE, manufacturing precision non-stick seals, high-grade gaskets, and chemical-proof insulators.
PVC
At Sundi MFG, we precisely process industrial-grade PVC, delivering highly durable fluid control valves, chemical processing equipment, and specialized electrical housing components.
CNC Machining Finishes
Sundi MFG offers a range of surface finishing options for custom machined parts. From corrosion protection to improved appearance and wear resistance, we help choose the right finish based on your material, application, and drawing requirements.
As Machined
Standard machined finish with visible tool marks, suitable for functional parts or further processing.
DLC Coating
A low-friction, wear-resistant coating for parts that require better surface hardness and longer service life.
PVD Coating
Thin durable coating improves wear resistance and surface protection without greatly changing dimensions.
Heat Treatment
Improves hardness, strength, and wear resistance for parts that need better mechanical performance.
Anodizing
Improves corrosion resistance and appearance for aluminum parts, with natural or colored options available.
Polishing
Reduces machining marks and improves surface smoothness for visible or functional surfaces.
Powder Coating
A durable colored coating for metal parts, often used on brackets, covers, housings, and visible components.
Black Oxidize
A dark conversion finish for steel parts, helping improve appearance and provide light corrosion resistance.
Brushed Finish
Creates a consistent directional texture for visible metal parts, panels, covers, and decorative components.
Electroplating
Adds a protective metal layer to improve corrosion resistance, wear resistance, or surface appearance.
Sand Blasting
Creates a uniform matte texture and helps remove minor machining marks before coating or final use.
Final surface finish depends on the base material, part geometry, tolerance requirements, and post-treatment process. If your drawing specifies a finish, coating thickness, color, or surface roughness, please include it in your RFQ.
CNC Machining Tolerances
| Allowed Variations in Millimeters for Specified Ranges of Nominal Lengths | fine | medium | coarse | very coarse |
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| 0.5 up to 3 | ±0.005 | ±0.1 | ±0.2 | - |
| over 3 up to 6 | ±0.005 | ±0.1 | ±0.3 | ±0.5 |
| over 6 up to 30 | ±0.01 | ±0.2 | ±0.5 | ±1.0 |
| over 30 up to 120 | ±0.015 | ±0.3 | ±0.8 | ±1.5 |
| over 120 up to 400 | ±0.2 | ±0.5 | ±1.2 | ±2.5 |
| over 400 up to 1000 | ±0.3 | ±0.8 | ±2.0 | ±4.0 |
| over 1000 up to 2000 | ±0.5 | ±1.2 | ±3.0 | ±6.0 |
| over 2000 up to 4000 | - | ±2.0 | ±4.0 | ±8.0 |
Manufacturing & Quality Capacity
We support custom CNC machined parts from prototypes to repeat production, with in-house machining, EDM, grinding, inspection, and documented quality control.
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Advanced Machining
Our facility is equipped with advanced machines from Seibu, Sodick, Makino, AMADA, Okamoto, Hurco, Haas, and Beijing Jingdiao, supporting CNC machining, Wire EDM, Sinker EDM, grinding, and high-speed milling for complex custom parts.
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Advanced Inspection Equipment
Key dimensions are checked with Zeiss CMM, Nikon profile projector, height gauges, micrometers, and other inspection tools before shipment.
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Certifications
Our ISO 9001:2015 quality system supports stable process control, inspection documentation, and consistent delivery for custom parts.
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Transparent Process
We keep production and inspection records throughout the process, helping ensure repeatability from prototype runs to repeat orders.
Why We Provide Engineer-Reviewed Quotes
We do not quote custom precision parts based solely on size or weight algorithms. Every submitted drawing is meticulously reviewed by our engineering team to assess machining feasibility, identify potential tolerance risks, verify material selection, and explore cost-saving routing options. This ensures you receive a highly accurate price, a realistic lead time, and a manufacturing plan that guarantees success.
Our Ordering Process
We are a direct-to-factory manufacturer, not a brokered quote platform. Every component is engineered, machined, and inspected in-house at Sundi. This ensures complete control over technical precision, production lead times, and data security from your initial drawing to final delivery.
Send RFQ
Submit your 2D/3D CAD models and technical specifications via our secure online form or direct email.
Review & Quote
Our technical team evaluates your drawings for manufacturability and provides a detailed, data-driven quotation within 12 hours.
Confirm Order
Finalize technical parameters, confirm tolerances, and lock in the production schedule prior to contract sign-off.
Production
CAM programming is executed, and production begins across our specialized CNC, EDM, or stamping lines.
Quality Inspection
In-process dimensional checks and a comprehensive final inspection ensure all parts meet specified tolerances before leaving the floor.
Packaging & Shipping
Components are meticulously packed using dedicated protective materials to prevent transit damage and shipped globally.
CNC Machining FAQs
What files do you need for a CNC machining quote?
For the most accurate quote, please provide a 3D CAD model (STEP, IGES) along with a 2D drawing (PDF, DWG) that explicitly calls out critical tolerances, threads, and surface finish requirements.
Can you hold tight tolerances for complex machined parts?
Yes. We typically hold ±0.01 mm for CNC operations. If your part requires tighter tolerances (down to ±0.002 mm), we utilize our in-house Precision Grinding and EDM centers.
Do you support low-volume and small-batch production?
Absolutely. We offer flexible manufacturing with no strict MOQ, supporting everything from a single custom prototype to reliable, low-volume repeat production batches.
Can you combine CNC machining with EDM or grinding?
Yes, this is one of our core strengths. If a part has internal sharp corners or utilizes ultra-hard materials that CNC cannot efficiently mill, we seamlessly transfer it to our Sinker/Wire EDM or Grinding departments under the same roof.
Do you provide inspection reports?
Yes, upon request, we can provide comprehensive quality documentation, including First Article Inspection (FAI) reports, material certificates, and detailed CMM reports.
