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Custom parts from China and the Czech Republic – parts made to your drawing, in series
We have custom parts made for you in series – from castings and CNC and sheet metal parts to finished assemblies, about 95 % from China, supplemented by partners in the Czech Republic. You have one contact person in Germany, and your contract and invoice are with a German GmbH. On this page you can see which process suits which part, what an enquiry needs and what the price depends on.
- Partner factories with EU experience
- One contact person in Jena
- China plus an EU second source in the Czech Republic
- Based in Jena since 2011
- Selected partner factories in China
- One contractual partner in Germany
- Pre-shipment inspection included
What are custom parts?
Custom parts are components that do not come from a catalogue but are made exactly to the customer’s technical drawing – with its dimensions, tolerances, materials and surface finishes. They are also called parts made to drawing, manufactured parts, special parts or contract manufacturing to drawing.
TOP Asia Technik has been sourcing such manufactured parts since 2011. Through our Chinese partner, we have access to a broad network of factories with experience in the EU market, many of which have worked for us for years. In addition to a fixed pool of partner factories, our partners and local agents – in China, the UK and the Czech Republic – actively look for new suppliers when a part requires it. That is why we are very open regarding part types, sizes and materials. For smaller quantities, short routes or a European second source, we use partners in the Czech Republic.
Our focus is the series demand of machine, plant, vehicle and equipment manufacturers. One-off parts or prototypes with no series to follow are usually better placed with a local manufacturer.
All part types at a glance
For every part type you will find materials, tolerances, design guidelines, cost drivers and typical questions. Your part is not listed? Send us your drawing anyway – we can source any part that is produced in series to a drawing.
Casting & forging
Aluminium die casting
Aluminium, zinc and magnesium die casting from China to your drawing: alloys, tolerances …
Investment casting
Investment castings in aluminium, stainless steel and steel to drawing: lost-wax process …
Castings (sand, ductile iron, cast steel)
Ductile iron, grey iron, cast steel and stainless steel castings to drawing: cast housings …
Counterweights
Counterweights for forklifts, cranes, construction and farm machinery to drawing: grey cast …
Forgings
Forgings to drawing: closed-die forgings, open-die forgings, rings and flanges in steel and …
Machining
CNC precision parts
CNC parts from China made to drawing: turned and milled parts in aluminium, steel, stainless …
Gears & drive components
Gears made to drawing and gearbox parts in series: spur gears, sprockets, shafts, splined …
Hydraulic manifolds
Hydraulic manifolds made to drawing in series: control and valve blocks in steel or aluminium …
Sheet metal, steelwork & profiles
Sheet metal parts
Sheet metal parts made to drawing in series: laser-cut, bent and welded parts in steel …
Enclosures
Sheet metal, stainless steel and aluminium enclosures made to drawing in series – with IP …
Stamped & deep-drawn parts
Stamped, stamped-and-bent and deep-drawn parts in series: progressive dies, fineblanking …
Machine frames & steel structures
Machine frames and steel structures made to drawing: welded, stress-relieved, machined and …
Vessels & tanks
Stainless steel vessels, tanks, hoppers and trays made to drawing in series – pickled …
Wire & tube bending
Bent wire and tube parts made to drawing in series from China: brackets, handles, frames. With …
Extruded profiles & heat sinks
Aluminium extrusions and heat sinks made to drawing: alloys, tolerances, die costs, anodising …
Plastics, rubber & sintering
Plastic injection moulding
Injection moulded parts made to drawing in series from China: material selection, shrinkage …
Toolmaking & mould making
Injection moulds, die casting dies or stamping dies from China: tool steel, SPI classes, tool …
Rubber parts
Moulded rubber parts, seals and rubber-to-metal parts made to drawing: NBR, EPDM, FKM …
Sintered Parts & MIM
Sintered and MIM parts made to drawing in series: structural parts, sintered bearings, metal …
Assemblies & electrical
Welded & Mechanical Assemblies
Welded and mechanical assemblies from China in series: welding standards, BOM, bought-in …
Cable Assemblies & Wiring Harnesses
Cable assemblies and wiring harnesses from China to drawing: crimping to IPC/WHMA-A-620 …
Electronic Assemblies
PCB assembly and electronics manufacturing from China: SMD/THT, IPC-A-610, AOI, X-ray …
Special topics
Special Fasteners & Springs
Special screws, springs and wire parts made to drawing in series: cold forming, ISO 898-1 …
Magnets
Custom magnets in series: neodymium magnets to drawing, ferrite, SmCo and magnetic assemblies …
Technical Ceramics
Technical ceramics to drawing in series: alumina, zirconia, silicon nitride, SiC and steatite …
Reverse Engineering
Reverse engineering of spare parts without drawings: 3D scan, material analysis, new drawing …
Manufacturing in the Czech Republic
Suppliers in the Czech Republic for parts made to drawing: smaller quantities, short lead …
Custom parts by process: what suits your part?
The overview shows which process is typical for which parts and which part sizes we cover through our network – larger parts on request. There is no fixed minimum order quantity: whether sourcing pays off depends on the part, quantity and tooling costs – talk to us.
| Process / part type | Typical parts | Part size (guide value) | Typical materials | More information |
|---|---|---|---|---|
| Aluminium die casting | Housings, covers, brackets with thin walls | a few grams to approx. 50 kg | EN AC-AlSi9Cu3(Fe), EN AC-AlSi12(Fe) | Aluminium die casting |
| Investment casting | Complex small and medium-sized parts, levers, pump parts | up to approx. 100 kg | 1.4308, 1.4408, 42CrMo4, AlSi7Mg | Investment casting |
| Sand and permanent mould casting | Bearing blocks, pump and gearbox housings, hubs | up to approx. 20 t (sand casting, ductile iron, cast steel) | EN-GJL-250, EN-GJS-400-15, cast steel, aluminium | Castings |
| Counterweights | Ballast and counterweights for forklifts, cranes, machines | up to approx. 20 t | Grey cast iron, steel | Counterweights |
| Forging | Flanges, levers, forks, highly loaded shafts | Closed-die forgings up to approx. 500 kg, rings up to approx. Ø 5,000 mm | C45, 42CrMo4, 1.4301 | Forged parts |
| CNC turning and milling | Shafts, bushings, plates, precision parts | Small parts to large parts of approx. 6,000 mm | Steel, stainless steel, aluminium, brass, POM | CNC precision parts |
| Gear cutting | Spur gears, pinions, sprockets, drive shafts | Gears up to approx. Ø 2,000 mm, shafts up to approx. 6,000 mm | 16MnCr5, 42CrMo4, C45 | Gears |
| Hydraulic blocks | Control blocks, valve and connection plates | up to approx. 1,000 mm edge length | EN AW-6082, S355, EN-GJS-400 | Hydraulic blocks |
| Laser cutting, bending, welding | Brackets, covers, bent parts | Bending lengths up to approx. 6 m | DC01, S235, 1.4301, EN AW-5754 | Sheet metal parts |
| Sheet metal housings | Control cabinets, panelling, equipment housings | up to approx. 3,000 mm | Powder-coated sheet steel, stainless steel, aluminium | Housings |
| Stamping and deep drawing | Clips, contacts, cups, sleeves | Large presses over 1,000 t in the network | DC04, 1.4301, CuZn37, spring steel | Stamped and deep-drawn parts |
| Steel construction | Base frames, machine frames, support structures | up to approx. 20 t | S235, S355 | Machine frames |
| Tank and container construction | Hydraulic and fuel tanks, trays | unpressurised, up to large tanks of several 10,000 l | S235, 1.4301, 1.4571, aluminium | Containers and tanks |
| Wire and tube bending | Brackets, lines, grids, handles | depending on the part | Spring steel wire, E235 tube, stainless steel | Wire and tube bent parts |
| Extrusion | Custom profiles, heat sinks, rails | depending on profile cross-section | EN AW-6060, EN AW-6063, EN AW-6082 | Extruded profiles |
| Plastic injection moulding | Housing shells, clips, gears, covers | depending on the part | PA6 GF30, PP, ABS, POM, PC | Plastic injection moulding |
| Toolmaking and mould making | Injection moulds, die casting dies, stamping tools | depending on the part | 1.2311, 1.2343, 1.2379 | Toolmaking |
| Moulded rubber parts | Seals, buffers, grommets, diaphragms | depending on the part | NBR, EPDM, FKM, VMQ | Rubber parts |
| Sintering and MIM | Small gears, levers, bearing bushings | mainly small and micro parts | Fe-Cu-C, 316L, 17-4PH | Sintered parts and MIM |
| Assembly | Welded and mechanical assemblies, ready-to-install modules | no fixed upper limit | Mixed construction | Assemblies |
| Cable assembly | Wiring harnesses, assembled cables | Limits per factory on request | Stranded copper wire, PVC, PUR, connectors | Cable assembly |
| Electronics manufacturing | Assembled PCBs, box build | Limits per factory on request | FR4, SMD and THT components | Electronic assemblies |
| Cold forming, spring coiling | Special screws, compression, extension and torsion springs | depending on the part | Quenched and tempered steel, 1.4401, spring steel wire | Special screws and springs |
| Magnet manufacturing | NdFeB, ferrite and SmCo magnets, magnetic holding systems | depending on the part | NdFeB, hard ferrite, SmCo | Magnets |
| Ceramics manufacturing | Insulators, wear and guide parts | up to approx. 500 mm, larger after individual review | Al2O3, ZrO2, SiC | Technical ceramics |
| Reproduction from a sample | Spare parts without a drawing | depending on the part | based on material analysis | Reverse engineering |
| Manufacturing in the EU | Small series, urgent demand, second source | up to welded assemblies of several 100 kg | Steel, aluminium, plastic | Czech Republic |
Matching manufactured parts to the right process: four rules of thumb
Often two or three processes are possible for one part. These questions narrow down the choice quickly.
Quantity over the product life
Tool-based processes such as die casting, injection moulding or stamping only pay off once the tool is amortised over several years. Calculate with the total demand over the product life, not with the first order.
Geometry first, material second
Undercuts, internal channels and strongly varying wall thicknesses point to casting. Prismatic parts with tight tolerances point to machining. Flat parts with constant thickness are almost always sheet metal or stamped parts.
Machine functional surfaces selectively
In series production, a cast blank with a few machined mating surfaces is usually much cheaper than a part milled entirely from solid. Mark in the drawing which surfaces really need to be machined.
Assembly instead of individual parts
If several custom parts are installed together anyway, it often pays to source them as an assembly: one inspection, one delivery, less logistics and goods receipt.
Requesting a quote for parts made to drawing: the data we need
The more complete the enquiry, the more reliable the quotation. Missing information almost always leads to questions or to prices with a safety margin. A detailed checklist is available in our guide How to prepare an enquiry with a drawing.
- 2D drawing as PDF with dimensions, tolerances, general tolerance (e.g. ISO 2768-mK) and revision status
- 3D model as STEP (alternatively IGES or Parasolid) – especially important for cast, injection-moulded and sheet metal parts
- Material with standard or material number, e.g. 1.4301 to EN 10088 rather than just “stainless steel”
- Surface finish and coating, such as powder coating with RAL colour, galvanising with coating thickness, or anodising
- Quantities: sample quantity, batch size per call-off and estimated annual volume
- Target price – welcome but not required: it helps the factories calculate realistically from the start
- Inspection requirements: first article inspection report (FAIR / EMPB), material certificate 3.1 to EN 10204, special characteristics
- Packaging and delivery location as well as preferred delivery terms (EXW, FOB, CIF or DDP)
How contract manufacturing to drawing works
Technical clarification
We check the drawing and data for manufacturability, clarify open points with you and suggest cost-reducing changes if needed.
Supplier selection and quotation
We select several suitable factories, obtain quotes and send you a quotation with part price, tooling costs and delivery terms.
Tooling and samples
After your order, the tool and first samples are made – in the best case after approx. 3 weeks, usually longer, up to approx. 10 weeks depending on complexity. You receive the samples with a measurement report, on request with a FAIR, for approval.
Series production with inspection plan
After your approval, series production runs to the agreed inspection plan, in approx. 4–8 weeks depending on quantity and complexity, plus transport. We monitor deadlines and escalate deviations with the factory.
Delivery and call-offs
As standard, we deliver to your door, duty paid and customs-cleared (DDP), as required as a single order, call-off order or from safety stock. More about how we work under Sourcing from China and Quality.
Cost drivers for custom parts
The part price is not just material and machine time. In practice, these points decide the price – and they can often be influenced in the drawing already.
Tooling costs and amortisation
In casting, injection moulding and stamping, the tool is often the largest single item. Tools from China often cost considerably less than in Germany – details in our guide Tooling costs in China.
Tolerances
Every tighter tolerance can mean an additional operation, slower machining or 100 % inspection. Use tight tolerances only on functional dimensions – more under Tolerances in the drawing.
Material and availability
Exotic materials or those rarely used in China increase price and lead time. There is often an equivalent, common grade to a GB standard – we are happy to check this with you.
Batch size and set-up costs
Set-up and inspection effort is spread over the quantity per batch. Larger, less frequent call-offs lower the unit price but tie up capital – call-off orders from safety stock are often the best compromise.
Surface finishes and post-treatment
Coating, hardening, anodising or vibratory finishing are separate process steps, often at sub-suppliers. Specifications in line with standards prevent expensive misunderstandings.
Freight, customs duty and packaging
Heavy parts of low value react strongly to freight costs, duty rates and any anti-dumping duties. A full-cost comparison up to your plant is therefore essential.
Custom parts from China or the Czech Republic?
Both routes have their strengths. We recommend the source per part – and combine them as main and second source if required.
Custom parts from China
China plays to its strengths with medium and large series, tooling-intensive parts and a high labour share, for example in welded and mechanical assemblies. You plan for longer transport times – usually several weeks by sea freight – through call-offs and safety stock.
Manufactured parts from the Czech Republic
The Czech Republic makes sense for smaller quantities, short-notice demand, when EU origin is required, or as a European second source against supply chain risks. Parts arrive by truck without customs clearance. The detailed comparison is on the page Suppliers in the Czech Republic.
When sourcing special parts through us pays off
A good fit if …
- Recurring series demand, also with call-off orders
- Custom parts with a high labour or tooling share
- Several part types you want to bundle through one contact person
- Existing parts for which you are looking for a cheaper source or a second source
Less suitable if …
- Individual prototypes with no foreseeable series
- Parts needed within a few days
- Catalogue and standard parts you can get from wholesalers
Frequently asked questions about custom parts
What is the difference between custom parts and standard parts?
Standard parts such as screws to ISO 4762 are standardised and available from stock. Custom parts are made to your individual drawing and exist only for your application. We source standard parts only as part of an assembly.
Is a 2D drawing enough or do you need a 3D model?
For turned parts and simple sheet metal parts, a fully dimensioned 2D drawing is often enough. For cast, injection-moulded and freeform parts, the factories need a 3D model as STEP because the tools are designed from it. The 2D drawing remains authoritative for tolerances.
Which standards apply to custom parts from China?
The standards stated in your drawing apply, such as ISO 2768 for general tolerances or EN material standards. Chinese factories often work to GB standards, so matching materials and test methods is part of the technical clarification.
Can I transfer an existing part from my current supplier?
Yes, that is a common case. What matters is the current drawing, samples from the running series and clarification of who owns existing tools. New tools in China are often cheaper than transferring old ones.
How do you make sure the parts match the drawing?
Through first samples with a measurement report or first article inspection report (FAIR / EMPB), a process approval and a series inspection plan. On request, we add 100 % inspection, inspection gauges, SPC and material certificates. Details on the Quality page.
What happens if the drawing changes during series production?
Send the new revision with the changes marked. We clarify the effects on tooling, price and schedule, and the factory produces to the new revision once new samples have been approved. You should plan for remaining stock of the old revision beforehand.
How quickly will I receive a quotation for custom parts?
That depends on the scope and completeness of the documents. For simple parts with complete documents, a quotation is usually possible within 1–2 weeks; complex parts and assemblies can take longer. You receive an initial response within 24 hours (on working days).
Downloads
Checklist: request for quotation to drawing
All the details for a fast, accurate quotation, ready to tick off. PDF.
Guide: sourcing parts from China
What buyers need to watch out for – from the enquiry to delivery. PDF.
Free downloadSend your drawing – get a quotation
Upload your drawing and 3D model, tell us the quantity and your deadline – we check feasibility and get back to you with questions or a quotation.
- Technical clarification before the request for quotation
- Quotations from audited partner factories
- One contact person in Germany
- Non-disclosure agreement (NDA) in advance on request
Prefer to call? 03641 9286337 · Mon–Fri 8 am–6 pm (CET)