What Is CNC Machining?
CNC machining is a subtractive manufacturing process. Computer-controlled cutting tools (end mills, drills, lathe tools) remove material from a solid block, bar or plate until what remains matches your drawing. There is no tooling to cut, no mould to build and no minimum run size. Your CAD file goes straight to the machine.
That makes CNC the right process when tolerances matter more than unit cost at volume: functional prototypes, low and mid-volume production, jigs and fixtures, replacement parts, and any component where a dimension has to be held to a specific number rather than a nominal one. Where injection moulding wins on cost per part at scale, CNC wins on accuracy, material choice and speed to first article.
At PlastFab Works we run precision CNC machining services across both metals and engineering plastics. Every job is machined in-house at our Mumbai facility. We do not subcontract. Every quote comes with a written DFM report before you commit material, not verbal feedback after something has gone wrong. If your part is plastic-only, see our dedicated CNC plastic machining services.
CNC Machining Services We Offer In-House
CNC Milling
3-axis and multi-axis milling of flat, profiled and pocketed geometry in metals and plastics. Brackets, enclosures, housings, manifolds, tooling plates. Tolerances to ±0.05 mm on critical features.
CNC Turning
Cylindrical components: shafts, bushings, spacers, flanges, rollers, custom fasteners. Turned in aluminium, steel, brass, nylon, Delrin and acetal. OD/ID tolerances to ±0.02 mm.
CNC Routing
Large-format flat profiles, sheet cutting and engraving. Acrylic panels, HDPE liners, signage blanks, gasket profiles and enclosure faces beyond standard mill envelope.
Drilling, Tapping & Reaming
Precision hole patterns, tapped threads, heat-set insert bores and reamed locating holes. Run as secondary operations or standalone on customer-supplied blanks.
CNC Milling Services
What we mill
Enclosures & housings
Machined from solid billet or plate. Pocketed interiors, sealed faces, tapped mounting bosses, cable gland cutouts.
Jigs, fixtures & tooling plates
Locating features, dowel bores, clamp slots. Reamed to ±0.02 mm where repeatable positioning matters.
Brackets & structural parts
Load-bearing geometry in aluminium and steel. Weight-reduction pockets, precision mounting hole patterns.
Milling removes material with a rotating cutter while the workpiece stays fixed. It is the right process for prismatic geometry: anything built from flat faces, pockets, slots, bosses and hole patterns rather than rotational forms.
Our CNC milling services cover 3-axis work as standard, with 4-axis indexing and 5 axis CNC machining available for parts with features on multiple faces or compound-angle surfaces. Most components do not need five axes. Where a part can be produced in two 3-axis setups for meaningfully less cost, we will say so in the DFM report rather than quoting the more expensive route by default.
Manifolds & fluid blocks
Cross-drilled porting, tapped fittings, sealing faces machined to specified surface finish.
Design note we flag often: internal corners in a milled pocket cannot be sharp, because the cutter is round. Specify a corner radius of at least one third of the pocket depth, or we will have to step down to an undersized tool, which is slower and more fragile. This is covered in our guide to design for manufacturing.
CNC Turning Services
Turning operations available-
OD turning and facing
stepped diameters, shoulders, tapers, chamfers
Thread cutting
metric and imperial, internal and external, to standard 6H/6g fit classes
Internal boring
precision bores held to reamed tolerance for bearing and press fits
Turning rotates the workpiece against a fixed cutting tool. Anything cylindrical, conical or threaded on a common axis is faster, cheaper and more accurate turned than milled.
Our CNC turning service produces shafts, bushings, spacers, rollers, adapters, flanged fittings and custom threaded components. Because the part rotates against a rigid tool rather than a cantilevered cutter, turning holds tighter diameters than milling. On precision OD and ID features ±0.02 mm is routine, against ±0.05 mm for equivalent milled work.
Grooving and parting
circlip grooves, O-ring seats, undercuts
Knurling
straight and diamond patterns for hand-grip features
Second-operation milling
flats, cross-holes and keyways on turned bodies
Capabilities, Tolerances & Materials
Materials we machine
Metals
Plastics
Aluminium 6061-T6
general structural, best all-round machinability
Aluminium 7075
high strength, aerospace-grade
Delrin / POM
tightest tolerances, low friction, gears and cams
Nylon PA6 / PA66
wear parts, bushings, self-lubricating
Stainless 304 / 316
corrosion resistance, food and marine
HDPE / UHMWPE
chemical resistance, food-safe grades
Mild steel
structural, cost-sensitive work
PTFE
seals, seats, extreme chemical resistance
Brass
fittings, electrical, decorative
Acrylic / Polycarbonate
optical clarity, guards, panels
Custom CNC Machining: How It Works
1
Submit your CAD file
STEP (.step / .stp) for 3D parts,
DXF for flat profiles,
plus a PDF drawing carrying tolerances, surface finish callouts and material specification.
Not sure what to send? Read how to prepare a CAD file for CNC machining.
2
Written DFM review and quote
Within two working days you receive a quote plus a written DFM report: features that add cost, tolerances that exceed process capability, material and geometry conflicts, and a recommended change with cost impact for each. Included at no charge, on every quote.
3
Confirm material and approve
You approve the quote and confirm material grade. Any DFM change you accept is reflected in a revised drawing before we cut metal.
4
Machining
Programmed, set up and machined in-house at our Mumbai facility. The engineer who quoted your part is the engineer who sets the machine.
5
Inspection and dispatch
Critical dimensions verified against your drawing and recorded on an inspection report that ships with the parts. Domestic and international courier dispatch, with commercial invoice and packing list for customs.
Why Source CNC Machining from India?
1
Cost, without a quality trade-off
Machining rates in India run materially below Western Europe and North America for equivalent tolerances. The saving comes from labour and overhead, not from looser standards or cheaper stock.
2
Engineering conversations in English
You are talking to the machinist, in English, about draft, fits and tolerances. No account manager relaying questions to a shop floor that never sees your intent.
3
Workable time zones
IST gives same-day overlap with Europe and the Gulf, and end-of-day handover with North America. Send a file at close of business, wake up to a DFM report.
Why Choose Plast Fab Works as your machining partner?
A written DFM report for every quote
Not a bullet point on a webpage. An actual document listing flagged features, the risk each carries and what changing it saves. Before you commit material.
The quoting engineer runs the machine
No handoff between the person who understood your part and the person who cuts it. Nothing gets lost in translation because there is no translation.
No minimum order
One prototype or five hundred production parts. Per-part price scales with quantity, but we do not impose a minimum batch charge to make a single piece worth quoting.
Not a 3D printing company that also does CNC. Not a marketplace routing your file to an unnamed shop. A machining and plastics manufacturer, with the machines on our own floor.
Need forming or welding as well as machining? See custom plastic fabrication. Moving to volume? See mould design and product design engineering.
Industries We Machine For
🚗 Automotive
Test fixtures, trim prototypes, under-bonnet brackets, jigs
🔬 Medical & Laboratory
Delrin and nylon fixtures, acrylic holders, clean-room components
🖥 Electronics & Enclosures
Machined housings, heat-sink plates, DIN components, panels
🏭 Industrial Automation
Wear pads, guides, manifolds, guarding, custom machine parts
✈️ Aerospace Ground Support
Tooling, handling fixtures, precision alignment components
🌊 Marine & Outdoor
Corrosion-resistant fittings, HDPE deck hardware, UV-stable covers
CNC Machining Frequently Asked Questions
1. What file format should I submit for CNC machining?
Send a STEP file (.step or .stp) for 3D machined parts and a DXF for 2D flat profiles. Always include a PDF drawing carrying tolerances, surface finish callouts and material specification. The 3D model defines geometry, the drawing defines functional requirements. We also accept IGES and SolidWorks native files. If there is a conflict between model and drawing, the drawing governs.
2. What tolerances can you hold on CNC machined parts?
Standard 3-axis milling is ±0.10 mm with ±0.05 mm achievable on critical features. CNC turning holds ±0.05 mm standard and ±0.02 mm on precision OD/ID. Reamed holes reach ±0.02 mm. Below that, features require grinding or lapping. For plastics, note that material behaviour in service matters as much as what we hold on the machine. Nylon absorbs moisture and moves after machining, while Delrin stays stable. Call out your critical dimensions and we will confirm achievability at quote.
3. Do you machine metals as well as plastics?
Yes. We machine aluminium 6061 and 7075, stainless 304 and 316, mild steel and brass, alongside the full engineering plastics range: Delrin, nylon, HDPE, UHMWPE, PTFE, acrylic, polycarbonate and ABS. PEEK and specialist grades on request. Tell us the grade at enquiry so we can confirm stock and machining approach.
4. What is your minimum order for custom CNC machined parts?
There is no minimum. We machine single prototypes and production batches alike. Per-part pricing is higher on single pieces because setup time is amortised across one part instead of many, but we do not apply a minimum batch charge or refuse small jobs.
5. Can I order CNC machining from overseas?
Yes. We ship regularly to Europe, North America, the Gulf and Southeast Asia. The process is fully remote: submit your STEP file and drawing, receive a quote with written DFM report within two working days, approve by email, and we dispatch by international courier on completion. Commercial invoice and packing list are provided for customs clearance. Lead time is typically 3–10 working days plus transit.
6. What quality documentation do you provide?
Every order ships with a dimensional inspection report confirming critical features are within drawing tolerance, and the written DFM report issued at quote stage. Material certification is available on request. Ask at enquiry so we can source certified stock. If your incoming inspection requires specific documentation formats, tell us before you approve the quote.
7. How is precision CNC machining priced?
Four things drive cost: machining time (geometry complexity and material removal volume), material cost and stock size, tolerance and finish requirements, and quantity. Tightening a tolerance from ±0.1 mm to ±0.02 mm on a feature that does not need it adds inspection and machining time to every part in every batch. The DFM report identifies exactly these cases so you can decide what is worth paying for.
8. Is there a CNC machining service near me?
Our facility is in Andheri East, Mumbai, and we serve clients across India and internationally. Because the full process from quote to dispatch runs remotely (file upload, emailed DFM report and quote, courier delivery), physical proximity makes no practical difference to lead time or quality. Most of our clients have never visited the workshop.
