Nozzle 2.0

Test object: HPA Test goal: Testing the new batch of accelerator diluted 1:1.

Test 1 1:1 Masterroc (167) 2 l/h + Duomix + HP 2.0 + Possolit retarder .1% (premix w.)
Test 2 1:1 Masterroc (167) 3 l/h + Duomix + HP 2.0 + Possolit retarder .1% (premix w.)
ratio water 0,18 van 0,17 (water tot premix)
Test 3 1:1 Masterroc (167) 4.5 l/h + Duomix + HP 2.0 + Possolit retarder .1% (premix w.)

Remarks:

• DT 3 was disabled (had influence on the readings of DT 2 and DT 1) (unfortunate) • Lars: Typical example of whatever

Test results: 1. More accelerator results in more fluctuations of the pressure in dt-2 2. The print was unevenly hardened. (left side vs right side of layer nozzle) 3. accelerator buffer vessel, started leaking due to pressure buildup. 4. Water / accelerator switching might cause instability / squirting.

Potential next tests:

Option 1: (Lars) 1. Printing with more retarder/plasticizer 2. Dilute accelerator more

Option 2: (Kees) 3. Higher water content in initial mix 4. More plasticizer/retarder (to minimize the fluctuations in pressure) 5. Less diluted accelerator (as buckling is primary failure mode)

General comment: 1. Printing the cylinder vs HPA (more standardized testing) 2. Test less, know more.

Time Remarks Measurement
14:06 Start Water dry-run Lmec
14:08 Connecting duo-mix to nozzle
14:11 dt-2 shows a readout error, there is a relationship between dt-1, dt-2 dt-3
14:20 Whatever, start the duomix
14:21 Stop Stop (duomix), DT 1 > 20 bar
14:22 DT 1 < 4 bar
14:23 Duo-mix start DT-1 2 bar
14:24 Duo-mix and water off (start accelerator)
14:27 Start nozzle, concrete is running 22.1˚C temp. amb.
14:31 Accelerator valve open Dt1- 3 bar
14:32 Nozzle speed 40% to 50%
14:32 Pressure dt-2 9 bar
14:34 Lmec on water
14:34 Duo-mix off

Conclusion setup:

- Pressure sensors work incorrectly, decided to do the test anyway.

Time Remarks Measurement
Start test 1
14:36 Ratio duo-mix water mixture 0.17 to 0.18
14:37 Nozzle start
14:38 Accelerator on
14:39 Start print, nozzle speed to 55%
14:40 Nozzle speed to 60%
14:40 Temperature nozzle Temp nozzle 38˚C
14:41 Dt-2 Stabilizes at 11 bar
14:42 Nozzle speed to 50%
14:44 Volkert suspects not enough accelerator on a “finger-test” on the initial layer Accelerator to 3l/h
14:45 Buckling failure layer 7. In the inside layer
14:46 Cleaning for test 2

Conclusion test 1:

Strength development of the concrete is slow with 2l/h Masterroc 1:1, buckling failure after layer 7.

Annotation Volker during printing: Change accelerator:water ratio, suggestion (Accelerator : water from 1:1 to 1:75)

Time Remarks Measurement
14:46 Start test 2
14:46 First layer 45% robot speed
14:47 Dt_2 steady at 10 bar
14:48 “Ripple formation” (print surface is ugly?)
14:49 Lars is going steady and the print too
14:52 Dt-2 steady 9.5 bar L0 31 ˚C
L5 38 ˚C
14:53 Pressure drops a little. (dt-2)
14:54 Bottom layer too soft, (assumption, the print object will fail)
14:55 Layer prints next to previous layer, buckling occurs. Layer 12 22.1˚C
14:56 Lmec accelerator to water

Conclusion test 2:

Stable results, increase in strength development with 3l/h Masterroc 1:1, printed layers from 7 to 12.

Annotation Kees: Interesting decrease in temperature, what could be the reason?

Time Remarks
14:58 Start test 3
14:59 Nozzle 30,3 ˚C, pressure dt-2 11.5
15:02 Start print, D-t 2 aggressive
15:02 visual squirting (probable due to air-bubbles)
15:03 55 seconds per layer (Robotspeed 45%)
15:04 Leaking pressure valve Lmec dt-2 10.5
15:06 Temperature Mortar 36.5 ˚C, 32 ˚C nozzle Mortar 36.5 ˚C
15:06 Squirting L0: 33 ˚C
15:07 D-t 2 unstable 11.5 bar
15:08 Noticeable difference in strength printed structure between test 3 and test 2 and 1.
15:08 Visual squirting.
15:06 Temperature Mortar 36.5 ˚C, 32 ˚C
15:08 Squirting
15:09 Pressure buildup Emec, leakage buffer vessel , stop test 3.

Conclusion test 3:

Pressure in DT_2 is fluctuating more in test 3. (15:04) Leaking of the pressure valve resulted in a slight drop in DT_2. Additionally the printed layers showed an uneven distribution of accelerator.

Pressure increased to 11.5 bar with an increase to 4.5 l/h.

  • data/nozzle-2.0.txt
  • Last modified: 2021/07/20 17:05
  • by kvriet