Sound familiar?
- The bureau rejected your file as non-manifold
- Thin walls broke off or simply did not print
- Two printed parts that should fit together are jammed solid
- Prints need so much support material that the surface is ruined
- You have an STL from the internet that needs changing and no way to edit it
Key facts
- Models designed for the specific process: FDM, SLA or SLS behave very differently
- Watertight (manifold) STL or 3MF files that slicers and bureaus accept first time
- Overhangs kept to about 45 degrees or less on FDM and SLA to reduce support material
- Clearances built in for parts that slide, snap or screw together
- Broken meshes from downloads or scans repaired or rebuilt as proper solids
- £45 an hour + VAT; printing is paid to the bureau or done on your own machine
FDM, SLA or SLS: design differs for each
| Process | How it works | Good for | Design watch-points |
|---|---|---|---|
| FDM | Melted plastic filament laid down layer by layer | Cheap prototypes, jigs, fixtures, larger parts | Visible layer lines, weaker across layers, overhangs need support, holes print slightly undersize |
| SLA | Liquid resin cured by light | Fine detail, smooth surfaces, small parts | Supports leave marks, hollow parts need drain holes, some resins are brittle |
| SLS | Nylon powder fused by laser | Tough functional parts, small batches, complex shapes | Unfused powder supports the part so overhangs are fine, but hollows need escape holes to remove powder |
Tell us which process you plan to use, or let us recommend one from what the part has to do. If you are not sure, we design for the more forgiving option and note what changes for the others.
Wall thickness, overhangs and detail
Published design guides from print bureaus vary, but a common starting point is walls of at least 1 to 1.2 mm on FDM, around 0.8 mm on SLA and around 1 mm on SLS, with more margin for anything load-bearing or tall and thin. We design above the minimum, not at it, because parts at the limit are the ones that fail.
On FDM and SLA, surfaces angled more than about 45 degrees from vertical generally need support. We reduce support by orienting the part well, adding chamfers instead of flat overhangs, splitting a part into printable pieces, and using teardrop-shaped horizontal holes on FDM. Embossed or engraved text needs to be big and deep enough to survive the layer height, and we size it accordingly. Always confirm the exact limits with your bureau for the material you choose.
Tolerances and fits
Printed parts are not exactly the size of the model. Plastic shrinks, nozzles squash, resin cures slightly oversize. For parts that fit together we design in a clearance gap suited to the process and fit: tighter for a press fit, looser for a sliding or rotating fit. For a critical fit we often suggest printing a small test coupon with a few clearance options before printing the whole part.
Holes that must be accurate can be printed undersize and drilled or reamed, and threads are often better as heat-set brass inserts than printed threads. Snap fits are designed with enough length to flex without snapping, and oriented so they do not break along a layer line.
STL, 3MF and clean meshes
STL is the long-standing print format: a surface of triangles with no units, so a part modelled in millimetres can arrive 25.4 times too big if the software assumes inches. 3MF is the newer format and keeps units, colour, multiple parts and print settings in one file, and many slicers now prefer it. We export whichever your bureau or printer wants, at a resolution where curves print smooth without making the file huge.
Every file is checked to be manifold (watertight, no holes, no flipped or overlapping faces). Meshes downloaded from model libraries or produced by 3D scans often fail this. We repair them, or rebuild them as proper solids in 3D CAD when they need editing, because editing a mesh directly is slow and imprecise.
Jigs, fixtures and spare parts
3D printing is not only for prototypes. Many small manufacturers print workshop aids: drilling and assembly jigs, soft jaws, gauges, cable guides, sensor brackets and protective covers. Designed properly, these can be made in an afternoon on an in-house printer instead of waiting for machined parts. We also model replacement parts for obsolete equipment, such as knobs, clips, covers and brackets, where the original maker no longer supplies them, provided you have the right to reproduce them. A worn sample and a few measurements are usually enough to start.
Price
Design for 3D printing is £45 an hour + VAT. Checking and fixing a single model can be well under an hour; a multi-part functional prototype is a bigger job that we usually fix-price. Printing is quoted and paid separately by your bureau. If the printed part is a step towards a manufactured product, see product design. Full prices.
What you get
- Print-ready STL or 3MF files, checked for errors
- STEP files of the same parts, for later machining or moulding
- Notes on recommended orientation and process
- Repaired or rebuilt versions of existing meshes
- A parametric source model, so sizes can be changed and re-exported
How it works and what it costs
Logos from £150, brochures from £295, photography from £295 a half day and CAD at £45 an hour, all + VAT. You get a fixed price before we start.
Tell us the brief
What it is for, who will see it, where it will be used and any examples you like. Rough is fine.
Fixed price
We confirm the price and what you get, in writing, before any work starts.
First designs
We design, shoot or model it and share the first version for your comments.
Refine
We make the changes, check every detail, and prepare the files properly for print, web or manufacture.
Final files
You get the finished files in the formats you need, ready for your printer, website, social channels or manufacturer.
Frequently asked questions
Do you do the 3D printing?
dijitul media designs and prepares the files. Printing is done on your own printer or by a printing bureau that you choose and pay directly. That way you can pick the right process and material, and we focus on making the file print properly first time.
What is the difference between STL and 3MF?
STL only describes the surface as triangles, with no units, colour or settings. 3MF keeps units, colours, multiple parts and print settings together, which avoids scaling mistakes. Most current slicers accept both. dijitul supplies whichever your printer or bureau prefers.
Which is better, FDM, SLA or SLS?
It depends on the part. FDM is cheapest and fine for jigs and rough prototypes. SLA gives fine detail and smooth surfaces for small display parts. SLS nylon is tough and needs no supports, so it suits functional parts and small batches. We recommend one based on what the part must do.
Can you fix an STL file that will not print?
Usually, yes. Common faults are holes in the mesh, flipped faces, overlapping shells and walls too thin to print. dijitul repairs the mesh, or rebuilds the part as an editable solid if it also needs changes, then exports a checked STL or 3MF.
Can a 3D printed prototype become an injection moulded part later?
Yes, but the design usually needs changes: moulded parts need draft angles, even wall thickness and no undercuts the tool cannot release. If we design with moulding in mind from the start, the jump from print to production costs less.
Related
Get a fixed price
Send a rough brief. You'll know exactly what it costs before we start.