How to get Complex Parts in Days, not Weeks
Need same day or quick turnaround CNC machining for complex parts? Learn what to send in your rush RFQ, design choices that save days, and how to balance speed, precision and FAIR/CMM documentation with Thompson Precision’s premium service.
If you are staring at a deadline with a critical part still on the screen, the difference between shipping on time and missing a gate often comes down to how well you specify the rush job. The right information helps a shop start immediately, choose the quickest manufacturing path and avoid rework. The wrong information adds hours of back‑and‑forth and can turn a two‑day turnaround into a week.
This guide is written for design engineers, buyers and project managers who need fast CNC machining for prototypes, test rigs, fixtures, enclosures and small production runs. It explains what a machining partner needs to move at full speed, the design choices that shave days from the schedule, and how to balance speed, precision and cost without risking quality.
Why listen to us
Thompson Precision specialises in quick turnaround machining, with typical lead times of around five days and expedited options that can deliver in as little as 12 hours when the scope allows. The team can quick‑turn 3, 4 and 5 axis milled parts up to about 2,000 by 1,000 by 600 millimetres and multi‑axis turned work, which makes it practical to rush both small and large components.
Capacity is part of the story. With more than 20 CNC centres and an in‑house premium service designed to fast‑track urgent orders, the shop is set up for time‑critical work. Quality control keeps pace too. A temperature‑controlled inspection department uses a large‑format Hexagon CMM running PC‑DMIS to generate automated reports and FAIRs, so you can ask for the documentation you need even on a tight schedule.
What Counts as a Rush CNC Job
A rush job is any order where manufacturing starts immediately after the RFQ and proceeds without idle time. That can be a same‑day prototype, a pre‑production fixture for a test campaign, or a recovery build when a supplier has slipped. The common thread is that the machining partner must be able to load data, choose material, program, set up, cut, inspect and dispatch in a straight run. The more friction you eliminate before the first toolpath, the faster everything goes.
The rush RFQ pack: what to send on day one
Here is the complete data pack that lets a CNC team start within hours. Treat it as your checklist and include only what matters to the function and deadline.
1. Clear goal and deadline
State the use case and the exact date and time the part must ship. If you can accept staged delivery, say so: for example, one part in 24 hours, the balance next week. If you are rescuing a project, include a one‑line summary of what went wrong so the team can watch for the same risks.
2. 3D CAD model
Send a single source of truth in STEP or native format that reflects the latest revision. If you have assembly context, include it. Keep names tidy and unique. If there are flexible design areas, flag them early so the machinist can propose faster alternatives.
3. 2D drawing with only the necessary tolerances
Use the drawing for GD&T, datums, threads and finishes. Mark critical‑to‑function features and let the rest run to a reasonable general tolerance. The fastest way to lose time is to tolerance everything tightly without a reason. If the part needs FAIRs or CMM reports, specify that here and call out any special report format. Thompson Precision can provide automated CMM reports and FAIRs, including on large parts, which is useful for first articles under time pressure.
4. Material grade and allowed substitutes
Pick common stock grades when possible, especially for rush work. If you can accept alternatives, list them in order of preference. Thompson Precision carries stock in common alloys and plastics and can often begin immediately, which is a big lever for speed.
5. Quantity and delivery profile
Tell the shop exactly how many you need now and how many later. A one‑off delivered tomorrow with a call‑off for ten the following week is often faster, because the team can optimise the first part for speed and the rest for efficiency.
6. Finish, colour and what is flexible
If cosmetic perfection is not essential for the first article, say so. Be explicit about acceptable alternates and what can be deferred. Thompson Precision routinely manages finishes such as anodising, electroless nickel and gold plating through partners, but choosing a simpler interim finish or shipping raw for the first part can save days.
7. Thread specifications and inserts
Call out thread forms, depths and any helicoils or inserts. If strength is more important than speed, say so. If speed is the priority, ask whether thread rolling, form taps or standard insert types can reduce cycle time or post‑processing.
8. Inspection level
Pick the lightest inspection that still protects function. For example, a CMM report on critical features plus a FAIR for the first‑off can be enough to proceed, with full documentation on the balance of the batch. Thompson Precision’s PC‑DMIS workflows are well suited to this staged approach.
9. Packing, labelling and shipping
Provide the delivery address, any special packaging needs and whether you can accept a same‑day courier. Small details like “bag individually, no tissue on anodised surfaces” prevent repacks and delays.
10. UHV or clean handling notes if applicable
If the part will see vacuum, include any cleanliness specification and whether you require a vented design. Thompson Precision can apply its own cleaning strategy or follow yours, which is important when outgassing and particle control matter.
Design Choices that Save Whole Days
A rush job is as much about design discipline as it is about cutting metal. These rules of thumb keep setups short, toolpaths stable and inspection simple.
Favour single‑setup machining
If the geometry allows, orient features for a single setup. Large‑format 5 axis machining can hit five faces without reclamping, which shortens programming and avoids stack‑ups. It is also a strong alternative to casting for low volumes because you skip pattern lead times and get parts in days rather than weeks.
Group tolerances by function
Put the tightest tolerances on bores, seats and datumed faces that truly drive performance. Let covers, cosmetic chamfers and non‑mating profiles run looser. This gives the machinist freedom to use larger, more rigid tools and faster strategies on the non‑critical areas.
Use sensible radii and access
Corner radii that match common cutter sizes are faster to program and cut. Avoid deep, narrow slots that require long stick‑out tools unless there is no alternative. If a pocket must be deep, consider adding a relief or access hole that allows a more stable tool.
Be deliberate about walls and floors
Thin walls and ultra‑flat floors add time. If stiffness and weight allow it, increase wall thickness slightly or permit a light scallop on floors. For housings, consider ribbing for stiffness rather than pushing every wall to a minimum.
Clarify threads and depths
Blind threads in deep pockets slow things down. Through‑holes with accessible starts are faster, as are standard thread depths that match available taps.
Reduce part handling
If the part is large, add temporary tabs or fixturing features that can be removed quickly. Thompson Precision’s large‑format capability makes single‑setup strategies practical on parts that would otherwise need multiple re‑clamps.
Choose materials and finishes that move fast
Material availability is often the biggest schedule driver after data quality. Here is how to keep it from slowing you down.
Prefer stocked grades
Common aluminium grades for machining and widely used stainless steels tend to be on the shelf. Thompson Precision holds stock in a range of metals and engineering plastics for exactly this reason. Ask what is on hand before you lock the spec.
Be flexible on plastics
If you are building a functional prototype, plastics like acetal or polycarbonate may machine faster than higher‑temperature polymers and still allow testing. If you do need PEEK or PTFE, flag it early so stock can be verified. Thompson Precision regularly machines engineering plastics as well as metals.
Pick a finish strategy that matches the deadline
If you can accept a two‑stage approach, ship the first article without finish or with a quick interim finish, then apply the final coating to the balance after sign‑off. The shop can also organise finishes like anodising and electroless nickel plating, which is convenient but does add lead time you should budget.
Inspection and Documentation
Many rush builds still require traceability. The trick is to set the minimum viable inspection plan 
for the first‑off and scale it up for the rest.
Ask for a first article with a focused CMM report
Target the features that matter and keep the report format simple. Thompson Precision’s PC‑DMIS‑driven CMM workflows support automated inspection and FAIRs, including for larger parts, which shortens the time between first chip and sign‑off.
Define acceptance up front
If you will accept a provisional approval on the first‑off so that machining can continue, say so in your RFQ. That lets the team cut while the report is being reviewed.
Special considerations for big parts and complex shapes
Large and complex does not have to mean slow. With large 5 axis capacity, a lot of what used to take three or four setups can be handled in one go, and in many cases milling from solid is faster than waiting for castings. If your design is trending toward casting for a small number of pieces, ask for a machined‑from‑solid alternative for the prototype and early build. The difference in lead time can be measured in weeks.
If the geometry is thin‑walled or has deep cavities, provide guidance on the faces that must remain pristine. That allows the shop to choose workholding that protects the right surfaces on the first clamp. When the part envelope pushes toward two metres by one metre, simple decisions about datum order and probe targets make a big difference, so call out a primary datum that the team can probe quickly on set‑up. Thompson Precision can rush large parts within those envelopes when the spec is clean.
If your part will see vacuum
Vacuum hardware has its own failure modes. Avoid blind holes that trap air unless they are vented. Deburr thoroughly, avoid adhesive residues and specify clean handling. If you have a cleaning protocol, include it. If not, ask the shop to apply its standard UHV cleaning and packaging strategy, which Thompson Precision can provide. This keeps outgassing and particle counts under control without adding unnecessary steps.
What Happens Inside a CNC Machining Job
It helps to know what the shop is doing with your data so you can anticipate questions.
1. Quick triage
The team checks for missing files, impossible tolerances and material availability. If anything will slow you down, you will hear about it immediately.
2. CAM programming and fixturing
Programmers build toolpaths and a probing routine, often in parallel with workholding design so set‑up is fast. On large or complex parts, 5 axis toolpaths reduce re‑clamps and shorten cycle time.
3. Cutting and in‑process checks
The machinist runs the job, pausing for quick checks on critical dimensions. If the risk is high, they will stop after the first operation to verify before continuing.
4. CMM and finish
For first articles, a CMM program runs to generate the dimensional report. If a finish is required and available within the deadline, the part goes straight to plating or anodising.
5. Pack and ship
Parts are packed to protect critical faces and shipped by dedicated courier when time is tight. If you stated staged delivery in your RFQ, the team continues cutting the remainder.
Common mistakes that kill speed
Avoid these and your odds of a true fast turnaround go way up.
• Missing or conflicting tolerances between the drawing and CAD
• Specifying a hard‑to‑source material when a common grade would do
• Tightening every dimension instead of only the ones that matter
• Calling for a finish on the first article when raw would be acceptable
• Not stating whether substitutes are allowed
• Leaving inspection requirements vague until the last minute
• Thread specs that need special taps or fixtures with long lead times
• Complex features on hidden faces that add setups without adding value
Your email template for a rush RFQ
Subject
Rush CNC RFQ – 1 off by [date time], [part name], [material]
Body
Hello,
We need a fast turnaround on the attached part. Details below.
• Deadline and delivery profile: 1 off by [date time], balance of 9 by [date].
• Material: 6082 preferred. 6061 acceptable.
• Finish: none on first‑off, black anodise on balance if schedule allows.
• Critical features: bores A and B, datum A plane, flatness on face C.
• Threads: M6 through, M4 blind x 8 mm.
• Inspection: FAIR for first‑off, CMM on critical features.
• Flexibility: small cosmetic blemishes acceptable on first‑off.
• Packing and shipping: bag individually, same‑day courier to [postcode].
Files attached: STEP model Rev C, PDF drawing Rev C.
Please confirm feasibility, delivery and price. If a change would reduce lead time, we are open to suggestions.
A quick checklist you can paste into your RFQ form
• Goal and deadline
• Quantity now, quantity later
• 3D model and drawing with only the necessary GD&T
• Material grade and allowed substitutes
• Finish requirements and acceptable alternates
• Thread callouts and inserts
• Critical‑to‑function features and datums
• Inspection level and report format
• Any UHV or clean handling needs
• Packing, labelling and shipping instructions
• Contact details for rapid replies
When every hour counts, the key is clarity. Give the shop only the information that protects function and delivery, be flexible where you can, and ask for the minimum viable inspection on the first‑off. If you want to fast‑track an order with Thompson Precision, the team is set up to move quickly, with the capacity, inspection tools and workflows to back it up.
