Printing TPU and Flexible Filament on the QIDI Q2: Complete Guide

The QIDI Q2 is an enclosed CoreXY printer with a 270×270×256mm build volume, a direct drive extruder (8.9:1 ratio, dual hardened steel gears), a 370 °C hotend and an actively heated chamber up to 65 °C — and it's that direct drive that makes it one of the friendliest entry-level machines for flexible TPU.

Flexible filament scares beginners: it buckles, jams in the feed path, strings everywhere and punishes you for rushing. But on the Q2, with its short feed path and strong grip, TPU 95A prints almost off the stock profiles — owners confirm it. This guide covers everything: picking a hardness, a full settings table, drying, bed adhesion, multi-color, and even flexible resin for SLA. For the printer's specs and behavior, see our QIDI Q2 review.

What TPU and flexible filaments are

TPE is the broad family of thermoplastic elastomers (rubber-like plastics), and TPU (thermoplastic polyurethane) is its most popular member: it has better layer adhesion and prints more easily. When filament is sold simply as "TPU" with no hardness listed, it's almost always 95A. Flexibility is measured on the Shore scale — the lower the number before the A, the softer the material.

• 95A — buy this first. Cases, straps, snap-fit hinges, dampers. Easy to print and holds its shape.
• 85-90A — soft grips, anti-slip feet, soles. Needs direct drive and patience.
• 98A and 60-64D — nearly rigid parts meant to absorb impact rather than flex: bumpers, spacers.
• The softer the material, the slower you print and the more critical dry filament becomes.

Why the QIDI Q2 is good at flexibles

The number-one enemy of flexible filament is a long feed path, where soft filament buckles and jams. The Q2 uses a direct drive: the motor and gears sit right above the hotend, the path is short, and two hardened gears with an 8.9:1 ratio grip TPU without slipping. The enclosed chamber keeps temperatures stable for stiffer flexible blends, and a strain gauge inside the hotend calibrates the first layer by touching the bed — that removes half the adhesion headaches with flexibles. For a full mechanical breakdown, see the QIDI Q2 review.

• Short feed path — soft filament has nowhere to buckle
• Hardened steel gears at 8.9:1 — strong, steady grip on TPU
• Strain gauge in the nozzle — flat first layer with no manual Z-offset
• Bimetal hardened nozzle — handles abrasive carbon-filled flexible blends too
• TPU 95A runs off the stock QIDI Studio profiles — no long tuning session

There's one caveat: the PTFE tube from the extruder to the hotend has a sharp bend on the Q2. It's a non-issue for 95A, but very soft TPU (below 85A) can buckle there. QIDI officially recommends 85A and harder on the Q2; anything softer will print, but needs low speeds and care.

Recommended TPU settings

The most reliable start is the stock TPU profile in QIDI Studio, or a ready-made profile from your filament's maker (Siraya Tech, for example, publishes OrcaSlicer profiles for its Flex 95A on QIDI printers). If you'd rather build a profile by hand, start from the table below — averaged working values from QIDI's official guide and owner practice. For OrcaSlicer specifics, see our OrcaSlicer guide.

A few rules that save hours. Enable combing so the head travels inside the perimeter rather than over open areas. Disable Z-hop: when the nozzle lifts, flexible filament has time to draw out into strings. Drop acceleration for flexibles to 3000-5000mm/s² — sharp jerks cause skipped steps and ghosting. And print one part at a time: fewer travel moves means less stringing.

Bed adhesion

TPU rarely has adhesion problems on the Q2 — if anything, parts stick too well. The stock textured PEI sheet holds most flexibles with no glue at all; owners print for days on end without prepping the bed. If adhesion does slip, wipe the sheet with isopropyl alcohol to remove finger oils. The smooth PEI side gives a glossy bottom, the textured side a matte and grippier one. General first-layer tips are in our first layer guide.

Drying and storing flexible filament

TPU is very hygroscopic — it soaks moisture from the air. Wet filament produces stringing, popping (crackle and bubbles at the nozzle) and weak layer adhesion. Dry TPU before every print: 50-60 °C for 4-6 hours in a dryer (40-70 °C depending on the brand). After drying, store it in an airtight box with silica gel — TPU starts re-absorbing moisture within an hour in open air. If you have a QIDI Box, it can dry spools at up to 65 °C while printing. More on moisture and drying in how to dry filament and the filament guide.

• Drying: 50-60 °C for 4-6 hours (soft 85A closer to 6-8 hours)
• Storage: airtight box with silica gel, never an open shelf
• Signs of wet TPU: crackle while printing, bubbles, torn layers, extra stringing
• A fresh vacuum-sealed spool can still be damp — dry it anyway

Fine tuning: retraction, pressure advance, cooling

Flexible filament acts like a spring: on retraction it stretches first, and only then does it actually pull back. So on direct drive, keep retraction short (0.5-1.5mm) and slow (15-20mm/s) — long, fast retractions just stretch the filament and cause jams. Pressure advance smooths nozzle pressure on corners and sharply reduces blobs; the exact value is tuned with a test, and for direct drive on Klipper it's usually 0.02-0.06. If you see under- or over-extrusion, check our under/over-extrusion guide.

• Retraction: start at 1.0mm / 20mm/s, reduce if you get jams
• Pressure advance: tune with a test tower, don't reuse PLA values
• Cooling: 50-70% for bridges and overhangs, 40-50% when you need layer strength
• Calibrate flow and PA per TPU brand — they differ noticeably
• Don't combine heavy cooling and ironing at once — pick one

Multi-color flexibles and the QIDI Box

Here's the letdown for anyone wanting colorful flexible parts: the QIDI Box and soft TPU don't mix. The unit has a long, friction-heavy feed path, and its minimum recommended hardness is around 64D — rigid engineering flexibles only. Tom's Hardware flatly recommends skipping the box, and other testers report jams in the path even with regular rigid materials. The takeaway is simple: print flexibles by direct feeding from the spool, one color at a time. A multi-color flexible part on the Q2 means manual filament swaps, not the box's automation.

Advanced mods for flexibles

If you've hit the ceiling of stock settings and want the most quality out of flexibles, there are a few firmware-level mods. The most useful is input shaper tuning. Out of the box the Q2 has a low accelerometer sample rate (400 Hz instead of 1600) and a Y axis that flexes slightly on fast moves — on flexibles this shows up as ghosting on the walls. The community (K3D, for example) recommends a heavier 2hump_ei shaper at ~80 Hz on both axes instead of the stock profile — the ringing drops noticeably.

• Input shaper 2hump_ei ~80 Hz on both axes — kills ghosting on flexible parts (intermediate)
• Adaptive bed mesh (KAMP) — enabled in printer.cfg, steadier first layer on large flexible parts (intermediate)
• Disable the spare AI service algo_app over SSH — less board heat and fewer hangs on long flexible prints (advanced)
• A ready-made filament-maker profile instead of manual tuning — the easiest path to a clean result (basic)
• Other weak spots and bugs of the model are in QIDI Q2 known issues and QIDI Q2 best mods

Common problems and fixes

• Stringing — TPU melt is runny; cut retraction to 1mm, drop temp in 5 °C steps, enable combing, disable Z-hop, dry the filament. Details in our stringing guide.
• Extruder jam — too-soft TPU or too much speed; drop to 20-30mm/s, loosen tension, check the PTFE bend. If the nozzle is truly clogged, see the clogging guide.
• Under-extrusion — wet filament or rushing; dry it, raise the nozzle 5-10 °C, slow down.
• Crackle and bubbles (popping) — that's moisture; dry at 50 °C for 4-6 hours.
• Weak layer adhesion — low temp or too much cooling; raise the nozzle, drop the fan to 40-50%.
• Part won't release from the bed — let the bed cool and the flex plate will release the print itself.

What to print with flexible filament

TPU is irreplaceable wherever a part has to bend, stretch or absorb impact. The classic is cases for phones and gear: they flex on a drop instead of cracking. Then come gaskets and seals (they outlast rubber and keep water out), ergonomic grips and anti-slip feet, vibration dampers, wheels and tracks for RC, and living hinges — flexible joints printed as part of the model.

• Cases and bumpers for phones, cameras, tools
• Gaskets, seals, O-rings
• Anti-slip feet, pads, grips
• Vibration dampers and shock absorbers
• Wheels, tracks and belts for RC and robots
• More to print in our roundup of things to 3D print

Flexible resin: the SLA alternative

If you have a resin (MSLA) printer next to your FDM machine, there's a second route to flexible parts — flexible and elastic resins. These cure into a rubber-like material. Their hardness is usually softer than typical TPU: Shore A 40-80 (Liqcreate Flexible-X is 55A with up to 160% elongation, Premium Flex is 63A). They run on open LCD/MSLA/DLP machines in the 385-420nm range. The upside of SLA is finer detail and a smooth surface; the downside is lower tear strength, higher cost and fussier post-processing (washing and post-curing, with parts staying a bit tacky). For resin printing tips, see our SLA resin troubleshooting guide.

Bottom line: where to start

1. Buy a spool of TPU 95A — the most forgiving start.
2. Dry it at 50-60 °C for 4-6 hours.
3. Use the stock TPU profile in QIDI Studio and feed directly (no QIDI Box).
4. Set retraction 1mm / 20mm/s, fan 60%, disable Z-hop, enable combing.
5. Print a stringing test, then dial in temperature and pressure advance.
6. Once comfortable, move on to 85A, input shaper tuning and harder parts.

Flexible filament likes a clean, well-kept printer: watch the extruder tension and the state of the nozzle — that's what our maintenance guide is for. And if you want to compare the approach on another machine, check the Snapmaker U1 TPU printing guide — many of the techniques carry over.

Sources

• QIDI Print Lab — official TPU settings for cases (95A and 85A)
• QIDI Q2 FAQ — supported materials and notes
• Tom's Hardware — QIDI Q2 Combo review ("skip the box")
• 3Dwork — QIDI Q2 review (8.9:1 direct drive, Box 64D)
• 3DToday — a week with the QIDI Q2 (real-world, TPU-95A)
• K3D — QIDI Q2 mods (input shaper, KAMP, algo_app)
• SpoolHound — TPU hardness comparison 85A/90A/95A/98A
• Liqcreate — flexible and elastic resins for SLA/MSLA