FAQsFrequently Asked Questions

Technical And Project Related Questions

What tolerances can you achieve?

There is not a given set of tolerances that fits all processes and materials. In every case, the final tolerances on your part will depend on a number of factors, including but not limited to:

Part size
Design geometry
The number, type and size of features
Surface finish
Manufacturing process

We will review your design and provide a design for manufacturing review, pointing out any areas where we may not be able to achieve your desired tolerances. It’s helpful to us if you can specify which areas in your design have critical tolerances that must be met and which can be slightly modified if needed to reduce time and costs involved. Here are some general tolerance guidelines:

Vacuum Casting

Tolerances for vacuum casting will depend on the tolerance of the master model, the type of casting resin being used, and the part’s geometry. Typically we apply a tolerance of + 0.15% deviation from the master model. For parts requiring heat treatment we may machine an insert such as Tufnol which prevents further shrinkage during heating.

SLA 3D printing

When using SLA, both typically have a lateral (X and Y axis) deviation of about + 0.1mm, and a vertical tolerance (Z axis) of + 0.3mm. Note that much finer tolerances than these can be achieved with post machining and finishing.

Unless otherwise specified, we comply with the DIN 16901 standard tolerances for plastic injection moldings. It is possible with careful thermal, time and pressure control to have very accurate parts. We need to know your requirements in advance so that we can manage key features in the tooling and molding process. As a general rule, you should never make more than one feature very accurate in the design. That feature can be repeated across the part, but to make a whole series of very different features very accurate is impossible for any molding company to achieve – you end up chasing your intolerances around the part. You get one feature right only to find another one slightly off.

CNC Machining

Our general tolerances for CNC machining of metals is DIN-2768-1-fine and for plastics DIN-2768-1-medium. Tolerances are greatly affected by wall thicknesses, material choice, and geometry, so we will seek to advise as to achievable tolerances for each part. We pride ourselves on wishing to help our clients achieve their desired tolerances that are better than DIN-2768-1, but we work on a “best effort basis only” if the tolerances stated are tighter than our stated standards. The reason we refuse to be held accountable for very tighter tolerances is that we are a prototype factory and very tight tolerances present a huge risk due to the nature of our work.

All manufacturing and technical specifications need to be clearly specified in the 2D drawings in order to be followed.

Can I get 'rapid injection molded' parts in days in the USA and Europe?

Yes, you can. But be forewarned that no company anywhere can give you quality injected molded parts in a few days. In order to make that deadline they must compromise on quality, meaning your part may need extra work later or be useful only as a non-functional prototype. You may also be expected to change your initial design greatly in order to accommodate a tight schedule. Star Rapid is able to make production quality injection molded parts in as little as two weeks. This time is not only realistic but we’re confident that no other supplier can do it as quickly, with equal quality and a better price. Injection mold tools made at mold-making.com aren’t designed to be disposable. They’re made from hardened and semi-hardened tool steel, with any surface finish or degree of complexity. The tool belongs to you, the customer, and with it you can run 50,000+ cycles using any commercially available grade of thermoplastic. That simply wouldn’t be possible if they were made in one or two days.

How do you ensure your quality?

In order to deliver high-quality parts every time, we’ve instituted the following steps to ensure you get parts that meet and exceed your expectations.

A full design for manufacturing (DFM) review upon initial inquiry. This will be performed by our skilled engineering team, who will alert you to any issues before work begins.
All incoming material (metal and plastic) is 100% inspected using our in-house metrology equipment. This includes OES, XRF and PolyMax spectroscopy.
In-process and first article inspection.
Comprehensive final inspection with full report.

What are shipping terms for rapid prototyping orders?

Our standard terms are Ex Works (EXW) for rapid prototyping and regular production orders. This means the customer is responsible for shipping, customs clearance and all other associated fees once the goods have left our premises.

Can I use my own material and/or master model for production?

Yes, customer-supplied material is fine so long as it fits with our machine capabilities, and we can use master models for vacuum casting copies.

Can you paint customer-supplied parts?

Yes, we can do custom paint work on your supplied parts, if they fit into our paint room.

Can I pay an express fee and get my parts sooner?

Of course. Since our terms are EXW, you may arrange shipping using any preferred method at your discretion.

Pricing And Shipping Related Questions

How does Molding Plastic compare to suppliers in the west on price?

This is a complex question with many variables. Some of the components include the cost of locally-sourced raw material vs. imported material, currency fluctuations between different countries, energy costs and how technology and labor-intensive a given project may be. In general, the greatest savings will be realized for labor-intensive projects, where local labor rates can be one-sixth their overseas’ counterparts, although this disparity is becoming more equalized as China develops. Historically speaking, averaged over many years and many types of products, we maintain a 30 % price advantage to our competitors in western countries Here are some other considerations: For SLA prototyping, there is no price advantage to making them in China. Quite the opposite, it will be much more expensive based on shipping costs alone. However, if 3D plastic printing is only the foundation for more extensive secondary processing (painting, sanding, overmolding, vacuum casting, etc.) then it starts to make sense. Vacuum casting prices can be 30-50% less than in the West, based on labor rates. The cost driver here is the price of imported Axson casting resin. Plastic injection mold tooling is consistently 50% of the pricing in Europe and America when using semi-hardened steels. Pressure die cast tools and processing is 25-50% cheaper. This is because there are no shortcuts to this process, and no way to do it “rapidly”. Die cast tools must be made carefully and fully heat-treated, which is labor intensive and time consuming. This is where great economies can be realized for aluminum and zinc die casting in particular, where the cost of raw material is not a big driver.

How does Molding Plastic compare to other Chinese suppliers on price?

Our prices will be between 50-100% more expensive than other Chinese suppliers. We are not embarrassed about this. Rather, it demonstrates our investment in the most skilled workforce including many foreign engineering experts, and we use high-quality imported equipment and materials in a modern factory with English-speaking staff. We are not competing against local suppliers, who cannot match our quality, delivery times, reliability or range of services. In other words, our quality is priceless.

How do delivery times compare to the West?

Clearly we cannot do overnight deliveries, but because of our proximity to major shipping and air transport hubs in Hong Kong, Shenzhen and Guangzhou we can have your parcel on an airplane within one day or less of leaving the factory. The speed of its arrival will depend on your specifying the type of air freight: priority express or normal air freight. Priority express can arrive at virtually any address within the lower 48 states within 48 hours of departure from Hong Kong. Heavier, bulk items that are not a shipping priority should go by ordinary sea freight, which is typically three weeks port-to-port, plus additional local shipment upon arrival.

What are the shipping terms for rapid tooling order samples?

Our standard terms are Delivered Duty Unpaid (DDU) for samples only. This means we assume all freight charges and liability to your named port of destination. The buyer then assumes responsibility for import duties and related local delivery.

How long does a quotation take?

In most cases, we respond within a couple of days of receiving an RFQ. However, there may be situations when we must source material from an external supply and therefore the quotation may be delayed accordingly.

How much import duty will I need to pay for my goods?

There is no single answer to this question but a few rules apply. For customers in Australia, new CHAFTA regulations allow for a progressive roll-out of duty-free import into Australia. Import duties vary widely between countries, and are dependent on the type of good being imported. Most countries in the world conform to the international Harmonized System (HS) codes that categorize virtually all commercial trade goods.

Company Related Questions

How do I know my design will be kept confidential?

First, we allow no photographs to be taken of your product or tooling without your express, written permission. No documentary information related to a customer’s product is allowed to leave the confines of the physical office, either in printed or electronic form, with the following exception: should it be necessary to perform some process on a customer’s part using an outside, third-party vendor, then the customer’s identifying information shall be removed from all relevant documentation. The outside vendor shall receive only that information necessary to their performance of the sub-contracted work. If we expect a breach of internal computer security, all transactions on all computers are automatically backed-up, 24/7, on secure servers in cHINA and can be traced back to individual user accounts if necessary. We will sign and abide by all NDAs to the limits of our ability. Ultimately, however, perfect security is not possible for ourselves or for any company, anywhere. In the vast majority of cases we don’t have access to the product in its final form, especially if it contains electronics and control software – often the very heart of proprietary information. It is in our long-term interest to maintain the highest level of trust with our customers. Should there ever be a case of missing or stolen data, we will work with you to pursue the matter to the limits of the law. Our reputation depends on it.

What if we are not completely satisfied with the parts we receive?

If it is practical to do so, we will replace free of charge any parts that you are not completely satisfied with. If that is not practical, then we will credit the customer a negotiated sum. Regarding plastic injection molded and pressure die cast samples: T1 (first trial of tooling) samples are never completely satisfactory, this is an industry norm. For example, T1 samples rarely carry the final finish/texture as the customer often finds the need to modify the design and have tooling changes made.