3D Printing Request: Material, Color, Tolerance

Lisa Ernst · 23.11.2025 · Technology · 7 min

The typical 3D printing email in our inbox sounds something like this: "Can you quickly print this part for me? File attached." No information about the material, no tolerances, no indication of whether the part is for a prototype, a machine, or just for display. Then the follow-up questions start – and "quick" turns into an annoying ping-pong of emails.

In our workshop at 33d.ch, we see such requests constantly. And just as often we see the opposite: clean, well-prepared projects where we can start working right after the first email and the customer gets exactly what they need. The difference is almost always in the details of the request.

This checklist shows which details should not be missing in a professional 3D printing request – from the file to material, color, and tolerance, to deadlines and budget. It helps you avoid follow-up questions, estimate costs better, and increase the chance that the part fits right the first time.

Quelle: Own Presentation

Request Basics

In our daily work, every 3D printing request boils down to four questions: What is being printed? With what is it being printed? What is it needed for? And how precisely does it need to fit? If your message covers these points, we can usually calculate and plan without detours.

1. Model and File Information

Without a clean file, the best material is useless. Many problems arise because the model is not print-ready or important file information is missing. This also happened to us in the beginning when we sent our own projects to external services – since then, we are very consistent with file specifications.

• File format: Standard formats like STL, OBJ oder 3MF work reliably with practically all slicers and online printing services.
• Dimensions and Scale: Write the external dimensions of the part (length × width × height in mm) in the request. In practice, we often see models that are correct in CAD but are suddenly loaded into the slicer in inches instead of millimeters.
• "Watertight" Model: The 3D model should be a closed mesh ("manifold") without holes or open edges. Only watertight STL files can be sliced stably and rarely lead to surprises.
• Unit: Clearly state whether the model is built in millimeters or inches. If we have to guess, scaling errors are almost pre-programmed.
• Version / Revision: Indicate whether it is the final version or a prototype. This is especially important if multiple versions are in circulation or – as with many professional service providers – clearly documented revisions are maintained.

At 33d.ch, we save the version directly in the filename (e.g., sensor_case_v3.2.stl) and use this designation in our order management. This way, everyone in the project is talking about the same version.

2. Material: PLA, PETG, ABS, Resin & Co.

The choice of material determines whether your part looks good, whether it softens in the car during summer, or whether it breaks after the first use. The "classic" FDM filaments PLA, PETG, ABS, and ASA already cover a large number of applications.

• Material class:
  • PLA: Very easy to print, little warping, ideal for sample parts and decorations. However, heat and outdoor use are not its strengths.
  • PETG: Tougher than PLA, good layer adhesion, often our standard for housings and functional parts in everyday use.
  • ABS/ASA: Heat-resistant and robust, but more demanding to print (warping, odor). ASA is usually more stable against UV for outdoor use.
• Printing process: State whether FDM/FFF (filament), SLA/DLP (resin), SLS/MJF (powder), or metal 3D printing is desired – if you already know. Tolerances and strength differ significantly depending on the process.
• Special requirements: Food contact, flame retardancy, ESD protection, or medical applications require special materials. Many filament overviews list typical special materials with their corresponding properties.

In our workshop, it has proven effective to first ask about the application and environment and only then suggest a material. Many customers come with "PLA is enough" – and we jointly discover that PETG causes significantly less trouble in the long run.

Quelle: 3ddruckservice24.de

Material Overview for 3D Printing

3. Color and Surface

Color is not just about appearance. It also helps to differentiate prototypes, label assemblies, or highlight specific functions. At the same time, the surface plays a role in handling and the professional impression of the component.

• Color preference: Ideally, specify a RAL tone or a clear description like "black matte". Many suppliers orient themselves by RAL-Farbreferenzen or fixed palettes.
• Surface:
  • FDM: Visible layer lines are normal – especially at a layer height of 0.2 mm. For design parts, we often reduce to 0.12 mm or less at 33d.ch.
  • SLA/DLP: Very smooth surfaces, but usually more brittle parts. Suitable for small, detailed geometries.
• Post-processing: Sanding, priming, painting, polishing, vapor smoothing, or threading should be mentioned in the request. This allows us to align the material, orientation, and support structures accordingly.

Especially for visible front parts, it has proven effective for us to state in the quote whether slight layers are acceptable or if "showroom-ready" finishing is desired. This avoids misunderstandings.

Application Details

The better we know the intended use, the more precisely we can suggest material, wall thicknesses, and tolerances. Different rules apply to a decorative model than to a lever in a machine.

4. Location, Load, and Environment

Many requests become significantly simpler when we have a sentence or two about the intended use. A housing for a sensor in a living room is different from a bracket in a production facility.

• Mechanical load: State whether it is a housing, a lever, a clamp, or purely a visual part. Material guides clearly distinguish between "functional parts" and "visual models".
• Temperature / Environment: Use outdoors, in a car, or near a machine with exhaust heat suggests PETG, ABS, or ASA rather than PLA. Such information is golden.
• Contact with media / chemicals: Contact with oil, cleaners, or solvents should be mentioned in the request. Material tables show which plastics typically withstand which media.

An example from our daily work: a customer from mechanical engineering initially wanted to have everything printed in PLA. After being informed about oil mist and elevated temperatures, we jointly switched to a more robust material – this prevented many field complaints.

5. Quantity, Series Planning, and Spare Parts

The planned quantity influences both the price and the choice of process. A different strategy is worthwhile for a single piece than for 200 recurring parts.

• Quantity and variants: State how many identical parts you need and whether variants with minor changes are planned. Many on-demand services offer price breaks from certain quantities.
• Repeat orders: If it's clear that the part will be reordered later, clean versioning and documentation of printing parameters are worthwhile. At 33d.ch, we maintain our own print profiles for such projects to ensure that repeat orders are reproducible.

Technical Specifications

This is where it's decided whether your part "fits approximately" or whether it can be assembled cleanly. Clear wording is particularly worthwhile for fits, holes, and sealing surfaces.

6. Tolerances, Fits, and Accuracy

Tolerances are not as strictly standardized in 3D printing as in traditional milling or turning, but there are proven guidelines. It is important that only truly functionally critical dimensions are tightly toleranced – otherwise, it becomes unnecessarily expensive.

• Rough tolerance guidelines: Many online printing services state typical tolerances for FDM of about ±0,5 % with a lower limit of approx. ±0.3–0.5 mm. SLA, SLS, and MJF are often in the range of ±0.2–0.3 % with lower limits around ±0.1–0.3 mm.
• Type of fit: State whether a clearance fit (easy sliding), a transition fit, or a press fit is desired. A Engineering-Fit-Guide clearly shows which clearances have proven effective for which type of fit.
• Mark functionally critical dimensions: Holes, connectors, and sealing surfaces should be clearly marked as critical (e.g., "Hole Ø10 H7 critical"). This allows us to measure specifically and, if necessary, slightly over- or under-dimension.
• Plan a test piece: For very tight fits, we recommend a small test piece with different hole or pin dimensions. In our workshop, we regularly print such "tolerance strips" before a larger series begins.

If you prefer watching videos: Recommended video (in English) on tolerances and technical fits in 3D printing: Watch YouTube video.

Quelle: heinz-engineering.com

Limit Deviations according to DIN ISO 2768-1

7. 7. Print Settings, Quality, and Infill

If you have specific print settings in mind, they should be included in the request. Otherwise, we will use reasonable default values – but these may be too soft, too coarse, or too heavy depending on the requirements.

• Layer height and infill: For classic FDM prints, beginner guides recommend a layer height of around 0,2 mm and an infill percentage of 20-30% for "normal" parts. Infill, simply put, is the interior of the component – from hollow to almost solid.
• Wall thickness / perimeters: For mechanically stressed parts, it is usually more sensible to use more perimeters (e.g., 3-4 outer walls) instead of extremely high infill values. This makes the part robust without using unnecessary material.
• Support strategy: Critical visible surfaces should ideally point upwards without support structures. Design guides recommend orienting components so that supports are only placed where they do not interfere with functionality.

At 33d.ch, for functional parts, we often explicitly discuss the balance between stability, weight, and print time. First-time customers often underestimate how much these parameters influence price and result.

Recommended video (in English) on slicer settings, layer height, and infill patterns: Watch YouTube video.

Organizational Matters

In addition to all technical details, deadlines, budget, and approvals also play a role. If these points are clear from the start, we can plan realistically – and you don't have to hope that "it will somehow work out".

8. Deadlines, Budget, and File Approval

This is where it's decided whether an order runs smoothly or whether we have to switch to express mode together.

• Deadline: State the desired delivery date and whether an express print is necessary. Many service providers have clearly defined surcharges for "Rush Orders" – at 33d.ch, we also communicate this openly.
• Budget range: A rough price range helps in selecting the process and materials. Depending on the combination, differences of a factor of 2-3 in the unit price are not uncommon.
• Permission for photos / references: A brief note on whether we can photograph parts and use them (anonymized) as references saves a follow-up question. Those who do not wish this will of course receive discreet handling of the data.

Quelle: proprintforge.com

Variety of Filament Colors

Example: Good 3D Printing Request

This is what a request looks like, with which we can work very efficiently in the workshop – without five follow-up questions and without guessing the material:

Subject: 3D Printing Request – Sensor Housing, FDM, PETG Black\n\nFile: "sensor_case_v3.2.stl", Unit mm, final version\n\nMaterial: PETG, preferably comparable to standard PETG for functional parts\n\nProcess: FDM/FFF\n\nColor/Surface: Black, rather matte; slight layer lines are okay\n\nApplication: Housing for temperature sensor indoors, max. 40 °C, no chemicals\n\nQuantity: 20 pcs. now, future reorders possible\n\nTolerances:\nOuter geometry ±0.3 mm is sufficient\nHole Ø10 mm for metal sleeve: as interference-free as possible, easy push-fit by hand\nSnap fits on the lid: rather tighter, I'll adjust the CAD if necessary\n\nPrint settings (desired): Layer height 0.2 mm, min. 3 perimeters, 30% infill, gyroid or cubic\n\nPost-processing: none, only support removal\n\nDelivery: Shipping within 7 days, standard shipping okay

With this type of request, we can create an offer very quickly and know exactly which points are critical. This aligns with recommendations from many design guides and service providers.

Example: Incomplete 3D Printing Request

Contrast program: A request that is friendly but raises more questions than it answers. We receive such emails regularly:

"Hey,\ncan you quickly print the part attached?\n\nIt's a housing for a sensor.\n\nColor doesn't matter, main thing is cheap.\n\nNeed it tomorrow.\nBest,"

Almost everything we need for a serious assessment is missing here: no material, no quantity, no information about the application, no tolerances, no realistic deadline estimate. The result: follow-up questions, uncertainty, and in the worst case, a part that is printed but not really usable.

Downloadable Checklist (PDF)

Precisely for these reasons, we work internally with a simple checklist that you can also use for your requests. Whether you're inquiring with 33d.ch or another service provider – with these points, you're on the safe side:

• Project Name / Reference
• Contact Details (Email, Phone Number)
• File Information
  • Filename
  • Format (STL/OBJ/3MF)
  • Unit (mm/inch)
• Material
  • desired material class (PLA, PETG, ABS, Resin, SLS, Metal…)
  • special requirements (temperature, UV, food contact, ESD…)
• Color & Surface
  • Color (e.g., RAL)
  • Surface requirement (visible layers ok? post-processed?)
• Application & Environment
  • mechanical function
  • temperature range
  • contact with media/chemicals
• Quantity & Series Planning
  • current quantity
  • expected repeat orders
• Tolerances & Fits
  • global tolerance range
  • list of functionally critical dimensions
• Print Quality
  • layer height
  • desired infill range
  • special requirements (e.g., weight, optics, strength)
• Deadlines & Other
  • desired delivery date
  • budget range
  • permission for photos/references

With such a checklist, recurring 3D printing projects become significantly more relaxed – for you and for the printing team.

In Summary

• The clearer your specifications for file, material, application, and tolerances, the fewer follow-up questions and surprises there will be.
• Explicitly mark functionally critical dimensions and fits – "everything as precise as possible" rarely leads to sensible offers.
• Consider framework conditions like quantity, deadlines, and budget so that the appropriate process can be chosen.
• Use a checklist to avoid forgetting important information – it's especially worthwhile for recurring projects.
• If you send us a request at 33d.ch, feel free to use this structure – so we can jointly get to the finished part faster.