A Practical Guide

Even the best 3D printers can run into issues from time to time. Warping, stringing, layer shifts, or under-extrusion can turn a promising print into frustration. Understanding what causes these problems — and how to fix them — is essential for anyone serious about consistent, high-quality results. In this guide, BritForge 3D explores the most common 3D printing issues and how to resolve them like a pro.

1. Warping and Curling

Warping happens when printed layers cool unevenly and pull away from the build plate. This is common with ABS and large flat prints. To reduce warping, use a heated bed, apply adhesive like glue stick or hairspray, and consider printing with a brim or raft. Enclosing the printer can also stabilise temperatures and prevent cool air drafts that trigger curling.

2. Poor Bed Adhesion

If your first layer isn’t sticking, the rest of your print is bound to fail. Check that your bed is level and clean, and that the nozzle is at the correct distance from the build surface (typically the thickness of a sheet of paper). Use bed adhesives or textured surfaces like PEI sheets for better grip. Slowing down the first layer speed can also help it stick properly.

3. Stringing or Oozing

Thin threads of filament between parts of your print are called stringing. This happens when the nozzle moves between locations without properly retracting the filament. To fix this, enable retraction in your slicer and increase retraction distance or speed. Also, check your print temperature — stringing often increases with overheating.

4. Layer Shifting

Layer shifting occurs when layers suddenly become misaligned, making your model look like it jumped mid-print. This is often caused by loose belts, stepper motor issues, or the print head crashing into a curled-up part of the print. Tighten your belts, ensure pulleys are secure, and reduce print speed slightly to improve accuracy.

5. Under-Extrusion

Under-extrusion means your printer isn’t pushing enough filament, resulting in weak prints with missing sections. Causes include a partially clogged nozzle, low flow rate, or incorrect filament diameter settings. Check your nozzle, increase flow rate slightly, and ensure your slicer matches your filament size (usually 1.75 mm).

6. Over-Extrusion

The opposite of under-extrusion, over-extrusion creates blobs, rough surfaces, or excess filament build-up. Try lowering the extrusion multiplier or flow rate in your slicer. Also ensure your filament diameter is properly calibrated — if your slicer thinks it’s smaller than it is, it’ll push too much material.

7. Visible Layer Lines and Poor Surface Finish

If your prints look rough or have inconsistent surface texture, it could be due to high layer height, vibration, or temperature fluctuations. Try reducing layer height for a finer finish, print at a lower speed, and isolate your printer from vibrations (using foam pads or a stable surface). Better cooling can also help smooth outer walls.

8. Nozzle Clogs

When nothing is coming out of your nozzle, or extrusion slows down dramatically, a clog is likely. First, try a cold pull using nylon or cleaning filament. If that doesn’t work, you may need to heat the nozzle and carefully push filament through manually or disassemble the hotend for a deep clean. Regular maintenance prevents this issue.

9. Filament Not Feeding

If the extruder motor clicks or your filament isn’t moving, check for tangles in the spool or blockage in the hotend. The drive gear may also be worn or clogged with plastic dust. Make sure your filament path is smooth, the spool rotates freely, and your extruder gears are clean and properly tensioned.

10. Print Stopping Mid-Way

Interrupted prints can result from power loss, corrupted SD cards, overheating stepper drivers, or firmware crashes. Always use high-quality SD cards and keep your firmware up to date. If possible, use printers with resume-on-power-loss features or UPS backup to avoid losing long prints. Monitor temperatures if issues persist during long jobs.

Conclusion

3D printing is a balance of hardware, software, and environment. Troubleshooting may seem daunting at first, but the more familiar you become with the symptoms and causes, the faster you’ll be able to act. At BritForge 3D, we apply this expertise to every job, ensuring our clients get perfect prints — every time. If your project requires reliability and quality, trust the experts. Upload your file today and let us take care of the rest.

Preserving Victorian Engineering Through Digital Manufacturing

The iconic “Penny Farthing” is one of the most recognisable bicycles in history, instantly identifiable by its oversized front wheel and much smaller rear wheel. However, despite the name becoming widely associated with the design, “Penny Farthing” was never actually its original name.

When these machines first appeared during the late 19th century, they were simply referred to as bicycles, and later became known more formally as the ordinary bicycle. The now-famous nickname only emerged later, inspired by the visual similarity between the large and small wheels and the size difference between the old British penny and farthing coins.

This particular example was originally built in 1879 by Humber, Marriott & Cooper, a company that would later become well known within British engineering and automotive history under the Humber name. Like many surviving examples of Victorian engineering, the bicycle represents not only an important stage in transport history but also a remarkable example of early mechanical design and manufacturing.

Over time, however, many original components on historic vehicles and machinery inevitably deteriorate through age, wear, and use. In this case, the original pedal foot rubbers had become worn and required replacement in order to preserve both the functionality and authenticity of the bicycle. Unfortunately, sourcing original replacement parts for machines of this age is rarely straightforward, with many components no longer commercially available in any form.

To help recreate the missing parts, BritForge3D used modern digital manufacturing techniques to produce accurate replacement pedal rubbers while still retaining the appearance and character of the originals. The process began by carefully assessing and measuring the surviving components so that replacement versions could be modelled accurately using CAD software.

The replacement pedal rubbers were then recreated in Fusion 360, allowing detailed 3D models to be produced and refined before manufacturing began. Using CAD modelling software made it possible to recreate the shape, dimensions, and mounting features of the original parts while ensuring the final replacements would fit correctly once installed onto the bicycle.

Process, Material Selection, Final Thoughts

The material selection also played an important role within the project. The replacement parts were produced using TPU, a flexible and durable 3D printing material commonly used where impact resistance and elasticity are required. Unlike rigid plastics, TPU provides a rubber-like flexibility, making it particularly well suited for components such as pedal rubbers that experience repeated contact and movement during use.

Using 3D printing technology allowed the replacement components to be manufactured efficiently without requiring expensive tooling or mould production. Traditional manufacturing methods for low-volume heritage parts can often be prohibitively expensive, particularly when only a small number of components are required. By contrast, additive manufacturing provides a practical and cost-effective solution for reproducing rare or obsolete parts in limited quantities.

Projects such as this highlight how modern 3D scanning, CAD modelling, and additive manufacturing technologies are increasingly being used within the heritage and restoration sectors. In many cases, these tools provide an opportunity to recreate parts that would otherwise be extremely difficult to source, helping preserve historically important machinery and vehicles for future generations.

The Penny Farthing itself also represents an important stage in the evolution of bicycle engineering. While visually striking, the design had significant limitations, particularly in terms of balance, safety, and gearing. Riders sat high above the ground, and because the pedals were connected directly to the large front wheel, stopping suddenly or striking uneven ground could easily result in serious accidents.

By the late 1880s, British inventor James Starley introduced the chain-driven rear-wheel bicycle, a development that would eventually lead to the modern “safety bicycle” design still used today. By separating pedal speed from wheel size through the use of chain gearing, bicycles could use smaller wheels while remaining faster, safer, and easier to ride. This innovation quickly made the ordinary bicycle obsolete, despite its iconic appearance and popularity during the Victorian era.

Today, surviving Penny Farthings remain an important reminder of early engineering innovation and the rapid development of personal transport during the Industrial Revolution. Restoring and preserving these machines is not simply about maintaining historic objects. It is also about preserving the craftsmanship, mechanical thinking, and engineering heritage that shaped modern transportation.

Projects such as this demonstrate how modern manufacturing technologies can now work alongside traditional restoration methods to help preserve engineering history. By combining CAD modelling, TPU 3D printing, and careful reproduction techniques, it becomes possible to recreate missing or worn components while still respecting the originality and character of the historic machine itself.