How can I be sure about the quality when the price is so low?
Quality assurance is a valid concern. The key is to separate the cost of production from the cost of quality assurance. Reputable suppliers maintain low production costs through scale and efficiency, not by skipping quality checks. You ensure quality by: 1) Choosing suppliers with relevant ISO certifications (e.g., 9001, 13485). 2) Starting with a small test order. 3) Requesting detailed inspection reports (with photos and CMM data) for your first few orders. 4) Using platforms that offer third-party inspection services. Many high-quality shops compete on price; your job is to find them through due diligence.
What are the typical lead times for prototypes and production runs?
Lead times vary dramatically based on part complexity and order volume. For simple, small-batch prototypes, many online services offer lead times as fast as 1-3 days for machining, plus shipping. For more complex prototypes or pre-production batches, 5-10 working days is common. For full production runs in the hundreds or thousands of parts, lead times can extend to 3-6 weeks to account for material procurement, production scheduling, and thorough quality inspection. Always confirm the lead time breakdown, as “5 days” may refer to machining time only, excluding shipping and customs.
Are tariffs and duties included in the quotes I see online?
This depends entirely on the platform or supplier. Many Western-facing online manufacturing platforms (like Xometry’s China service) now include estimated duties and tariffs in the final quoted price to the customer, providing “landed cost” clarity. When dealing directly with a factory on Alibaba or via a direct email quote, the price is almost always EXW (Ex-Works), meaning you own and pay for all logistics, insurance, and import costs from their factory door. It is critical to ask this question upfront and, if needed, work with a freight forwarder to get a realistic total cost.
What file formats do I need to provide for a quote?
Standard 3D CAD file formats are required for automated quoting and manufacturing. The most universally accepted and preferred format is STEP (.stp or .step), as it contains robust 3D geometry data without being tied to a specific CAD software. IGES (.igs) is also widely accepted. While some platforms may accept native files like SOLIDWORKS (.sldprt) or AutoCAD (.dwg), a STEP file is your safest bet to ensure your design is interpreted correctly and to avoid errors in the quoting process.
Can I get both metal and plastic parts from the same supplier?
Absolutely. The majority of comprehensive CNC machining service providers in China, especially the larger online platforms and integrated factories, machine both metals (aluminum, steel, brass, titanium) and plastics (ABS, Nylon, POM, PEEK). This is a significant advantage, allowing you to consolidate sourcing for assemblies that contain multiple materials. Be sure to check their material list to confirm they stock or can source the specific alloy or plastic grade you require.
How do I handle communication and avoid misunderstandings due to language or time zones?
Successful communication is built on clear processes. Use visual aids: mark up drawings, use screenshots, and create simple bullet-point lists for requirements. Many suppliers have English-speaking sales and engineering staff. For technical details, use universally understood engineering terminology and symbols from your drawings. Embrace asynchronous communication via email or project management platforms, which creates a written record. Alternatively, using a managed service that has a Western-based project management team (as noted in the Xometry example) entirely removes the language and time-zone barrier, though it may come at a slight premium.
Is it safe to pay upfront to a new supplier in China?
Standard payment terms with new suppliers often involve a significant upfront deposit (e.g., 30-50%) with the balance paid before shipment. To mitigate risk: 1) Use secure payment methods with some recourse, such as PayPal (though fees are high) or credit card payments through a platform. 2) For larger orders, consider using a letter of credit (LC) facilitated through your bank. 3) Leverage trade assurance programs offered by platforms like Alibaba, which can provide payment protection if the order is not fulfilled as agreed. Building trust starts with smaller orders.