摘要
目的研究3D打印钥匙技术开锁案件的勘验重点和检验方法。方法使用常见的进口PLA、国产PLA、不锈钢合金、光敏树脂四种打印材料制作3D钥匙,开锁后通过体式显微镜和扫描电镜观察锁芯内的残留物和痕迹,与原配钥匙、传统增配钥匙开锁后的留痕比较区分,并使用显微红外光谱仪检测残留物成分。结果PLA、不锈钢合金、光敏树脂3D钥匙均能成功地无损开启门锁。其中PLA、光敏树脂打印钥匙开锁后会在锁芯内残留少量的打印材料碎屑,通过显微红外光谱检测法可鉴别区分残留物的材料种类;与原配钥匙和传统增配钥匙相比,不锈钢合金打印钥匙开锁后在锁芯内弹子弧面端遗留擦划痕迹的概率更大;同时,非金属的3D打印钥匙一经使用便会在钥匙体上形成难以修复的污损、磨损痕迹。结论锁芯内的微量残留物和内弹子上的微观痕迹是3D打印钥匙开锁后的主要留痕,显微红外光谱检测法和扫描电镜观察法可鉴别不同材料打印钥匙的留痕。
Objective To explore the investigating focal points and techniques about 3D-printed keys after unboltinglocks.Methods 3D-printed keys were manufactured with four commonly-used materials-polylactic acid(PLA),both ofimported and domestic;stainless-steel alloy and UV-curable resin.The newly-made 3D-printed keys,after unclosing locks,were examined with stereomicroscopy and scanning electron microscopy to detect the left remnants and marks(unlockingmarks),plus the micro-infrared spectroscopy being used to have the spectra of 3D-printed-key-left remnants comparedand differentiated against those from the original and traditionally-copied keys.Results Those 3D-printed keys,made ofPLA,stainless-steel alloy and UV-curable resin,were all able to open the lock without causing functional damages.Amongthe keys,the one made of PLA or UV-curable resin had left in the cylinder of lock the remnants that can be identified withmicro-infrared spectrometer.Compared to the original and traditionally-copied key,the key made of stainless-steel alloywas more liable to leave marks on the curved face of spring bolt.Besides,stains and abrasions had permanently remainedon the nonmetallic 3D-printed key once used.Conclusions 3D-printed key,if used,will leave remnants in the lock cylinderand microcosmic marks on the spring bolt.These remnants and marks can be further differentiated through micro-infraredspectroscopy and scanning electron microscopy for recognizing the specific materials made into the 3D-printed keys.
作者
陶梦霞
俞纲
陈峰
TAO Mengxia;YU Gang;CHEN Feng(Institute of Forensic Science,Xihu Branch of Hangzhou Public Security Bureau,Hangzhou 310023,China;Institute of Forensic Science,Xiaoshan Branch of Hangzhou Public Security Bureau,Hangzhou 311200,China)
出处
《刑事技术》
2019年第5期416-420,共5页
Forensic Science and Technology
关键词
开锁痕迹
显微红外光谱
扫描电镜
3D打印钥匙
unlocking marks
micro-infrared spectrometer
scanning electron microscope(SEM)
3D-printed key
