Voir la source de Factors Affecting Arrow Head Accuracy

{{Tuto Details
|Main_Picture=TM016_Arrow_Head_Adjustment_on_Saw_image9.jpg
|Main_Picture_annotation={"version":"2.4.6","objects":[{"type":"image","version":"2.4.6","originX":"left","originY":"top","left":-258,"top":-193,"width":859,"height":646,"fill":"rgb(0,0,0)","stroke":null,"strokeWidth":0,"strokeDashArray":null,"strokeLineCap":"butt","strokeDashOffset":0,"strokeLineJoin":"miter","strokeMiterLimit":4,"scaleX":1.19,"scaleY":1.19,"angle":0,"flipX":false,"flipY":false,"opacity":1,"shadow":null,"visible":true,"clipTo":null,"backgroundColor":"","fillRule":"nonzero","paintFirst":"fill","globalCompositeOperation":"source-over","transformMatrix":null,"skewX":0,"skewY":0,"crossOrigin":"","cropX":0,"cropY":0,"src":"https://stuga.dokit.app/images/b/b8/TM016_Arrow_Head_Adjustment_on_Saw_image9.jpg","filters":[]}],"height":450,"width":600}
|Description=<translate>Additional root causes that can affect arrow head accuracy</translate>
|Categories=Maintenance
}}
<translate>=Machine Types=
Arrow head setup on a Stuga machine falls into 3 different groups depending on the model of the machine and the centralising options fitted
<br />
{| class="wikitable"
!
!Standard
!Full SY Axis
!Y-Drive
!Notes
|-
|''Description''
|''Direct centralising on simple cylinder''
|No mechanical centralising, all on an axis
|
|
|-
|Standalone Saw
|All
|
|
|
|-
|Flowline / ZX3 / ZX4
|
|
|Optional Refurbished with Y-Drive
|
|-
|Microline
|
|All
|
|
|-
|Autoflow
|
|All
|
|
|-
|ZX5
|
|
|All
|
|}

=T Transoms First=
{{Info|..If you can't get T shapes correct,  the you will never get Z profiles correct, so it is important to get reliability and repeatability on simple profiles first}}


The first important step is to gather reliable test data. Create test pieces 4 off 400mm of narrow, mid and wide T transoms 

*Carefully check that the bars are symmetrical
*Use a test bar long enough to ensure the offcut is not at the start of the bar
{{Info|...We want to test the system where the first cut is an arrow head with infeed clamping only. If an offcut is at the start of the bar, it will be clamped on both infeed and outfeed side.}}

*Label them 1, 2 and 3 and 4 as they come off the machine
*Carefully check the dimensions and symmetry of each profile - use the "front to front and back to front method" to check shoulder lengths against each other. This is a quick way to identify discrepancies and compare pieces
*Measure the arrow head location accurately and carefully to get an idea of how the arrow heads perform overall, rather than concentrating on one profile that the operator tells you is wrong.
*If there are any inconsistencies on a profile, repeat the same test - Do you get the same result?
*Test inconsistent profiles again - do you get the same result?
{{Info|...It is important to get consistent inconsistencies to be able to understand what to do about it}}<br />
{| class="wikitable"
|+Root Cause Table - All Saw, Flowline, ZX3/4/5
!Symptoms
!Potential Root Cause
!Checks
|-
|No issues found but history of:

*All arrow heads out by the same amount on one bar or a set of bars in order, then correct again

*Arrow heads out by a long way (>5mm) towards front of machine

*Mitre cut lengths also short (not long)
|Swarf or offcut stuck was stopping the centralise getting to position


Top clamp pressure too high

Centralise cylinder pressure too low

(either / both will stop profile getting pushed to backfence)


Centralise cylinder leaking past seal


Centralise slideway system jammed / not lubricated / failure
|Check the side fence reaches the profile when centralising


Check clamp pressures top1-2bar, centralise 2-2.5bar






Check centralise slideway mechanicals and lubrication
|-
|First or last arrow head on bar is different to others
|Side fences not parallel
Rear fences not aligned
|[[TM016 Arrow Head Adjustment on Saw#Step 4 - Check Side Fences are Parallel]]
|-
|Some profile arrow heads correct, others profiles not. <u>Repeatable results on every test</u>
|Arrow head offsets (fiddle factors) historically set
|Reset all ofsets to zero before starting
|}<br />
{| class="wikitable"
|+Root Cause Table - SY Drive Only (Refurb Flowlines with SY upgrade, All ZX5s)
!Symptoms
!Potential Root Cause
!Checks
|-
| rowspan="2" |Arrow heads varying with no pattern, changes after redatum
SY axis stalling and has following errors 
|SY axis needs lubricating
|Check SY axis moves full range of movement by hand and via drives screen
|-
|SY axis sensor not functioning correctly
|
|-
|All arrow heads out by same amount
|SY Axis Datum is wrong
|Check and double check offsets
Check repeatability of SY axis datum visually (mark a line and repeatedly test datuming) 
{{Warning|..You have to ask yourself why the SY axis datum position has changed - there has to be a root cause. Simply changing the parameter will mask the real problem and therefore guaranteed to return again minutes or days later}}<br />
|}

=Z Transoms Second=
Repeat the same tests for Z shaped profiles
<br />
{| class="wikitable"
|+Root Cause Table AFTER T Transoms correct - All Saw, Flowline, ZX3/4/5
!Symptoms
!Potential Root Cause
!Checks
|-
|Bottom arrow head is different to top
First or last arrow head on bar is different to others
|Z Support not active for profile
Z support incorrectly set for profile rebate

Infeed top clamp pressure not high enough to flatten profile
|Check Z support settings
Manually check how the Z profile is clamped with the Z support out

Top Clamp pressure 1bar-2bar
|-
|One profile incorrect but others ok
|Profile not symmetrical
|Test Z transom Symmetry (can be difficult!)
|-
|Some arrow heads correct, others not, but fixed pattern, not varying along bar length
|Arrow head offsets (fiddle factors) historically set
|Reset all ofsets to zero before starting
|}</translate>
{{PageLang
|Language=en
|SourceLanguage=none
|IsTranslation=0
}}
{{AddComments}}
{{Tuto Status
|Complete=Draft
}}